全文获取类型
收费全文 | 2860篇 |
免费 | 148篇 |
国内免费 | 14篇 |
学科分类
医药卫生 | 3022篇 |
出版年
2024年 | 6篇 |
2023年 | 29篇 |
2022年 | 52篇 |
2021年 | 94篇 |
2020年 | 59篇 |
2019年 | 52篇 |
2018年 | 89篇 |
2017年 | 65篇 |
2016年 | 59篇 |
2015年 | 86篇 |
2014年 | 94篇 |
2013年 | 150篇 |
2012年 | 233篇 |
2011年 | 218篇 |
2010年 | 121篇 |
2009年 | 109篇 |
2008年 | 204篇 |
2007年 | 248篇 |
2006年 | 212篇 |
2005年 | 180篇 |
2004年 | 186篇 |
2003年 | 140篇 |
2002年 | 121篇 |
2001年 | 22篇 |
2000年 | 20篇 |
1999年 | 24篇 |
1998年 | 24篇 |
1997年 | 16篇 |
1996年 | 20篇 |
1995年 | 15篇 |
1994年 | 7篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有3022条查询结果,搜索用时 0 毫秒
1.
Accuracy evaluation of image registration and segmentation tools used in conformal treatment planning of prostate cancer. 总被引:1,自引:0,他引:1
Stefania Pallotta Marta Bucciolini Serenella Russo Cinzia Talamonti Talamonti Cinzia Giampaolo Biti 《Computerized medical imaging and graphics》2006,30(1):1-7
Segmentation and registration tools are commonly used in radiotherapy for target and at risk organs localisation. In this work the performances of three different segmentation tools and of a surface matching registration technique, used on computed tomography (CT) and magnetic resonance (MR) images for the treatment planning of conformal prostate carcinoma, are studied. The accuracy of the segmentation and registration tools was evaluated by phantom experiment and on patient data, respectively. A preliminary estimate of MR image distortion was also performed. 相似文献
2.
Gregory C Gray Troy McCarthy Mark G Lebeck David P Schnurr Kevin L Russell Adriana E Kajon Marie L Landry Diane S Leland Gregory A Storch Christine C Ginocchio Christine C Robinson Gail J Demmler Michael A Saubolle Sue C Kehl Rangaraj Selvarangan Melissa B Miller James D Chappell Danielle M Zerr Deanna L Kiska Diane C Halstead Ana W Capuano Sharon F Setterquist Margaret L Chorazy Jeffrey D Dawson Dean D Erdman 《Clinical infectious diseases》2007,45(9):1120-1131
BACKGROUND: Recently, epidemiological and clinical data have revealed important changes with regard to clinical adenovirus infection, including alterations in antigenic presentation, geographical distribution, and virulence of the virus. METHODS: In an effort to better understand the epidemiology of clinical adenovirus infection in the United States, we adopted a new molecular adenovirus typing technique to study clinical adenovirus isolates collected from 22 medical facilities over a 25-month period during 2004-2006. A hexon gene sequence typing method was used to characterize 2237 clinical adenovirus-positive specimens, comparing their sequences with those of the 51 currently recognized prototype human adenovirus strains. In a blinded comparison, this method performed well and was much faster than the classic serologic typing method. RESULTS: Among civilians, the most prevalent adenovirus types were types 3 (prevalence, 34.6%), 2 (24.3%), 1 (17.7%), and 5 (5.3%). Among military trainees, the most prevalent types were types 4 (prevalence, 92.8%), 3 (2.6%), and 21 (2.4%). CONCLUSIONS: For both populations, we observed a statistically significant increasing trend of adenovirus type 21 detection over time. Among adenovirus isolates recovered from specimens from civilians, 50% were associated with hospitalization, 19.6% with a chronic disease condition, 11% with a bone marrow or solid organ transplantation, 7.4% with intensive care unit stay, and 4.2% with a cancer diagnosis. Multivariable risk factor modeling for adenovirus disease severity found that age <7 years (odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4-7.4), chronic disease (OR, 3.6; 95% CI, 2.6-5.1), recent transplantation (OR, 2.7; 95% CI, 1.3-5.2), and adenovirus type 5 (OR, 2.7; 95% CI, 1.5-4.7) or type 21 infection (OR, 7.6; 95% CI, 2.6-22.3) increased the risk of severe disease. 相似文献
3.
Cinzia Bressi Cesare Maria Cornaggia Massimiliano Beghi Matteo Porcellana Ilaria Ida Iandoli Giordano Invernizzi 《Seizure》2007,16(5):417-423
PURPOSE: To verify the emotional components expressed by the relatives of adult patients with a diagnosis of epilepsy, and whether they are related to adjustment to the illness and the course of the illness over time. METHODS: We studied a consecutive sample of 43 outpatients suffering from epilepsy and 43 key relatives using the Camberwell Family Interview (CFI), with the expressed emotion (EE) of the relatives being rated at baseline (T0). EE refers to a construct representing some key aspects of interpersonal relationships: the relatives were assigned to the high-EE group if they scored 3 or more on the emotional over involvement (EOI) scale, or showed hostility, or made 6 or more critical comments. The patients were clinically evaluated at baseline and for 1 year of appropriate treatment by an epileptologist who was blinded to the EE ratings. They also completed STAI XI, STAI X2 and Beck's Depression Inventory at baseline. RESULTS: Twenty-six relatives (60%) were rated as showing a high degree of EE. In the 12-month follow-up study, high EE and high EOI were found to be associated with a significantly higher seizure frequency than that recorded for the patients living in low-EE households (p<0.05). The patients from households assessed as reflecting a high degree of criticism showed poor drug compliance (p<0.01), whereas those with relatives assessed as having a high degree of warmth showed better clinical and pharmacological compliance (p<0.01). High family criticism scores also correlated with higher study entry levels of depression (p<0.05) and trait and state anxiety (p<0.05) among the patients. CONCLUSIONS: The study findings highlight the impact of particular components of the family emotional climate on the clinical course and psychological adjustment of patients with epilepsy. 相似文献
4.
Cinzia Azzoni Tiziana D’Adda Guido Tamburrano Carlo Coscelli Ole D. Madsen Lucio Scopsi C. Bordi 《Virchows Archiv : an international journal of pathology》1998,433(6):495-504
Sixty-seven insulinomas were investigated by immunohistochemistry using site-directed antibodies against insulin, proinsulin, chromogranin A, HISL-19, and four proteins directly or indirectly involved in the proteolytic processing of proinsulin: the prohormone convertases PC2 and PC3, carboxypeptidase H (CPH) and 7B2. Results were expressed in a six-grade score according to the frequency of immunoreactive tumour cells. Insulin was expressed by all tumours, appearing in either a diffuse or a polarized pattern and being detected in more than 30% of tumour cells in all cases but three. Proinsulin was also expressed in all tumours, with more than 50% of tumour cells immunoreactive in all cases but 5. It was consistently localized in the Golgi apparatus. In about half the cases, moreover, it also showed diffuse cytoplasmic staining, usually with a very sparse distribution. Trabecular and solid insulinomas did not present specific, homogeneous patterns of insulin immunostaining. However, insulin immunoreactivity was much more abundant in trabecular than in solid neoplasms, being present in virtually all tumour cells (score 6) in 50% and 8% of cases, respectively. Virtually all insulinomas expressed PC2, PC3, CPH and 7B2, usually in 30–100% of tumour cells, with a frequency significantly related to that of insulin. However, detection of PC2 and 7B2 was slightly less frequent than that of PC3 and CPH. In consecutive sections these proteins were found to be mostly co-localized with insulin and chromogranin A but not with proinsulin. They were heavily expressed in all 10 tumours with more than 10% of cells showing cytoplasmic proinsulin immunoreactivity, indicating that the leakage of proinsulin from the Golgi compartment is not associated with faulty expression of converting enzymes and possibly reflects a saturated processing capacity. HISL-19 immunoreactivity was found in both Golgi apparatus and insulin stores, indicating that the relevant antigen is different from all other proteins investigated. These results do not support a defect in expression or localization of proinsulin-processing enzymes in most insulinomas. 相似文献
5.
A MicroRNA signature associated with prognosis and progression in chronic lymphocytic leukemia 总被引:2,自引:0,他引:2
6.
Cinzia Dello Russo Anne I Boullerne Vitaliy Gavrilyuk Douglas L Feinstein 《Journal of neuroinflammation》2004,1(1):1-15
Background
Under pathological conditions, microglia produce proinflammatory mediators which contribute to neurologic damage, and whose levels can be modulated by endogenous factors including neurotransmitters such as norepinephrine (NE). We investigated the ability of NE to suppress microglial activation, in particular its effects on induction and activity of the inducible form of nitric oxide synthase (NOS2) and the possible role that IL-1β plays in that response.Methods
Rat cortical microglia were stimulated with bacterial lipopolysaccharide (LPS) to induce NOS2 expression (assessed by nitrite and nitrate accumulation, NO production, and NOS2 mRNA levels) and IL-1β release (assessed by ELISA). Effects of NE were examined by co-incubating cells with different concentrations of NE, adrenergic receptor agonists and antagonists, cAMP analogs, and protein kinase (PK) A and adenylate cyclase (AC) inhibitors. Effects on the NFκB:IκB pathway were examined by using selective a NFκB inhibitor and measuring IκBα protein levels by western blots. A role for IL-1β in NOS2 induction was tested by examining effects of caspase-1 inhibitors and using caspase-1 deficient cells.Results
LPS caused a time-dependent increase in NOS2 mRNA levels and NO production; which was blocked by a selective NFκB inhibitor. NE dose-dependently reduced NOS2 expression and NO generation, via activation of β2-adrenergic receptors (β2-ARs), and reduced loss of inhibitory IkBα protein. NE effects were replicated by dibutyryl-cyclic AMP. However, co-incubation with either PKA or AC inhibitors did not reverse suppressive effects of NE, but instead reduced nitrite production. A role for IL-1β was suggested since NE potently blocked microglial IL-1β production. However, incubation with a caspase-1 inhibitor, which reduced IL-1β levels, had no effect on NO production; incubation with IL-receptor antagonist had biphasic effects on nitrite production; and NE inhibited nitrite production in caspase-1 deficient microglia.Conclusions
NE reduces microglial NOS2 expression and IL-1β production, however IL-1β does not play a critical role in NOS2 induction nor in mediating NE suppressive effects. Changes in magnitude or kinetics of cAMP may modulate NOS2 induction as well as suppression by NE. These results suggest that dysregulation of the central cathecolaminergic system may contribute to detrimental inflammatory responses and brain damage in neurological disease or trauma. 相似文献7.
8.
9.
Malignancy-associated allelic losses on the X-chromosome in foregut but not in midgut endocrine tumours 总被引:2,自引:0,他引:2
Pizzi S D'Adda T Azzoni C Rindi G Grigolato P Pasquali C Corleto VD Delle Fave G Bordi C 《The Journal of pathology》2002,196(4):401-407
Information on genetic changes involved in the progression of gastroenteropancreatic (GEP) endocrine tumours is scanty. On the other hand, the identification of molecular markers of malignancy could be crucial for the prognostic evaluation of these neoplasms, which is hardly predictable on the basis of conventional histological criteria. An association of X-chromosome deletions with malignancy has already been found in gastric endocrine tumours. To investigate this further, a comparative loss of heterozygosity (LOH) analysis was performed on 17 pancreatic endocrine tumours (PETs) and 17 intestinal (ten ileal, six appendiceal, and one rectal) carcinoids from female patients. The relationship of X-chromosome LOH with the ploidy status of the neoplasms was also investigated. LOH was found in six of eight malignant PETs (60% of the informative markers), but was infrequent in the nine benign ones (4.5%). In contrast, although retention of heterozygosity was consistently observed in benign midgut tumours, LOH was infrequent in malignant carcinoids (15%). No correlation was found between LOH and the ploidy status. These results indicate an association between X-chromosome LOH and malignancy in foregut endocrine tumours. The lack of such an association in midgut carcinoids suggests that different molecular mechanisms are involved in the progression of these two categories of endocrine neoplasms, which are otherwise considered to be closely related. These findings emphasize the need for further molecular studies on GEP endocrine tumours, carefully subdivided according to their anatomical site of origin. 相似文献
10.
Human herpesvirus 8 seroprevalence and evaluation of nonsexual transmission routes by detection of DNA in clinical specimens from human immunodeficiency virus-seronegative patients from central and southern Italy, with and without Kaposi's sarcoma 下载免费PDF全文
Cattani P Capuano M Cerimele F La Parola IL Santangelo R Masini C Cerimele D Fadda G 《Journal of clinical microbiology》1999,37(4):1150-1153
In order to investigate the seroprevalence of human herpesvirus 8 (HHV-8) infection in central and southern Italy, sera from human immunodeficiency virus (HIV)-seronegative subjects, with and without Kaposi's sarcoma (KS), were analyzed by immunofluorescence assay, using BC-3, a cell line latently infected with HHV-8. High titers of antibody against HHV-8 lytic and latent antigens were detected in all 50 KS patients studied, while in 50 HIV-seronegative subjects without KS, 32 (64%) were found positive for HHV-8 antibodies. Titers in the sera of these patients were lower than those for KS patients. This data suggests that HHV-8 infection is not restricted to KS patients and that the prevalence of HHV-8 infection in the general population may be correlated with differing rates of prevalence of KS in different parts of the world. In view of these findings, possible nonsexual transmission routes were evaluated. Nested PCR was used to test for the presence of HHV-8 DNA in saliva, urine, and tonsillar swabs from KS and non-KS patients. In KS patients, 14 out of 32 tonsillar swabs (43.7%), 11 out of 24 saliva samples (45.8%), and just 2 out of 24 urine samples (8.3%) tested positive for HHV-8 DNA. In the control group, on the contrary, none of the 20 saliva and 20 urine specimens was positive for HHV-8 DNA; only 1 out of 22 tonsillar swabs gave a positive result. This data supports the hypothesis that HHV-8 infects the general population in a latent form. The reactivation of viral infection may result in salivary shedding of HHV-8, contributing to viral spread by nonsexual transmission routes. 相似文献