全文获取类型
收费全文 | 428篇 |
免费 | 29篇 |
国内免费 | 13篇 |
学科分类
医药卫生 | 470篇 |
出版年
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 9篇 |
2011年 | 9篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 1篇 |
2007年 | 13篇 |
2006年 | 11篇 |
2005年 | 10篇 |
2004年 | 5篇 |
2003年 | 10篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 24篇 |
1997年 | 23篇 |
1996年 | 17篇 |
1995年 | 23篇 |
1994年 | 20篇 |
1993年 | 33篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 9篇 |
1989年 | 17篇 |
1988年 | 21篇 |
1987年 | 34篇 |
1986年 | 21篇 |
1985年 | 20篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 12篇 |
1980年 | 12篇 |
1979年 | 1篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1971年 | 1篇 |
排序方式: 共有470条查询结果,搜索用时 375 毫秒
31.
Khan RB Boop FA Onar A Sanford RA 《中国神经肿瘤杂志》2006,4(2):142-142
OBJECT: The goals of this study were to define the incidence of seizures in children with low-grade tumors, study seizure outcome after lesionectomy in these children, and identify risk factors for poor seizure outcome, METHODS: The authors performed a retrospective chart review of children who harbored low-grade brain tumors, experienced seizures, and were treated in a single institution, Statistical analyses included step-wise as well as single-variable binary logistic regression analyses. 相似文献
32.
Ki-ras mutations are an early event and correlate with tumor stage in transplacentally-induced murine lung tumors 总被引:2,自引:2,他引:2
Leone-Kabler S; Wessner LL; McEntee MF; D'Agostino RB Jr; Miller MS 《Carcinogenesis》1997,18(6):1163-1168
A previous study from this laboratory demonstrated that treatment of
pregnant mice with 3-methylcholanthrene (MC) caused lung tumors in the
offspring at 1 year after birth, the incidence of which correlated with
fetal inducibility of Cyp1a1. Analysis by PCR amplification and allele-
specific hybridization (ASO) of paraffin-embedded tumors generated from
that study revealed the presence of point mutations in exon 1 of the Ki-
ras gene. This work has now been expanded by PCR amplification and ASO
analysis of 31 additional lesions. Point mutations were found in 37 of the
47 (79%) lesions analyzed in this and the previous study, the majority of
which were G-->T transversions in the first or second base of codon 12.
The mutational spectrum appeared to be dependent on the relative stage of
differentiation of the lesion, as both the incidence of mutation and type
of mutation produced correlated with malignant progression. Mutations
occurred in 60% of the hyperplasias, 80% of the adenomas and 100% of the
adenocarcinomas. In the lesions with mutations, GLY12-->CYS12
transversions occurred in 100% of the hyperplasias, 42% of the adenomas and
14% of the adenocarcinomas. The GLY12-->VAL12 transversions occurred in
none of the hyperplasias, 42% of the adenomas and 57% of the
adenocarcinomas. The remaining mutations, which consisted of ASP12
transitions and ARG13 transversions, occurred only in adenomas (17%) and
adenocarcinomas (29%). Between this study and our previous analyses, the
identity of the mutations obtained by ASO were confirmed by sequence
analysis of eight of the 37 lesions that harbored mutations at the Ki-ras
gene locus. There were no differences in the type or incidence of mutations
relative to the metabolic phenotype or sex of the mice. These data suggest
that mutational activation of the Ki-ras gene locus is an early event in
transplacental lung tumorigenesis, and that the type of mutations produced
by exposure to chemical carcinogens can influence the carcinogenic
potential of the tumor. This may have prognostic significance in
determining the malignant progression of the neoplasm.
相似文献
33.
AS Grumach RC Carmona D Lazarotti MA Ribeiro RB Rozentraub ML Racz A Weinberg MMS Carneiro-Sampaio 《Acta paediatrica (Oslo, Norway : 1992)》1993,82(3):284-290
Breast milk samples from three groups of Brazilian women were evaluated: G1, mothers delivering term babies of low birth weight (n=16); G2, mothers delivering preterm babies of appropriate birth weight (n = 20); G3, mothers delivering term babies of appropriate birth weight ( n = 30). Milk samples were obtained at 48 h and on the 7th, 15th, 30th and 60th days after delivery and they were analyzed for lysozyme and total IgA levels and for the presence of specific antibodies against Poliovirus types I, II, III, Rotavirus, Herpes simplex virus, Varicella zoster and Cytomegalovirus. The groups were not statistically different in relation to mother's age, parity, type of delivery or socio-economic levels. IgA levels were higher in both low-birth-weight groups (G1 & G2) compared to the control group (G3) throughout the study period. Lysozyme levels decreased up to the 15th day, increasing thereafter up to the 60th day in all groups. Specific antibodies were detected throughout the study period, with no differences among groups. We conclude that breast milk composition of mothers delivering low-birth-weight babies (G1 & G2) was similar despite the different gestational ages. 相似文献
34.
Early pregnancy complications: endovaginal sonographic findings correlated with human chorionic gonadotropin levels 总被引:2,自引:0,他引:2
Endovaginal sonography results were compared with quantitatively determined human chorionic gonadotropin (hCG) levels in 84 women referred for early pregnancy complications. Of the 27 with normal intrauterine pregnancies, an intrauterine gestational sac was prospectively identified in one of five cases (20%) in which hCG levels were below 500 IU/L (Second International Standard), four of five (80%) with hCG levels of 500-1,000 IU/L, and all 17 with hCG levels above 1,000 IU/L. In comparison, 17 of the 26 women with ectopic pregnancies (65%) had hCG levels greater than 1,000 IU/L, and none of the 26 had an intrauterine gestational sac. Endovaginal sonography demonstrated an adnexal mass and/or a gestational sac-like structure in 16 of the 17 cases (94%) in which hCG levels were above 1,000 IU/L, compared with only three of the nine (33%) with lower hCG levels (P less than .01). These findings indicate that an intrauterine gestational sac should be normally visualized with endovaginal sonography when the hCG level exceeds 1,000 IU/L, and that visualization of an extrauterine gestational sac and/or adnexal mass is significantly more likely in ectopic pregnancies when the hCG level exceeds 1,000 IU/L. 相似文献
35.
36.
Background
In view of increase in incidence of exptrapulmonary tuberculosis after the epidemic of human immunodeficiency virus infection, the clinical profile of extrapulmonary tuberculosis in patients with HIV infection was studied.Method
The study population comprised patients of HIV infection with extrapulmonary tuberculosis. Work up included history, clinical examination, sputum for acid fast bacilli, chext X-ray, ultrasonography (USG) abdomen, fine needle aspiration cytology(FNAC), transbronchial needle aspiration (TBNA) and computed tomography of chest.Results
There were 50 cases, all males with mean age of 35 years. 24(48%) were without pulmonary tuberculosis and 26(52%) had pulmonary tuberculosis. 41(82%) had disseminated disease and 9(18%) involve one site. Fever and weight loss were the most frequent symptoms (79% and 58% respectively) in cases without pulmonary tuberculosis. The most frequent extrapulmonary site was lymph node in 46(92%), followed by spleen in 13(26%), pleura 9(18%), miliary 7(14%) and hepatic 1(2%). The diagnosis was confirmed by invasive methods in 30 out of 50(60%) cases [FNAC in 23(88%), TBNA in 2(25%) and pleural biopsy in 5(55%)].Conclusion
In HIV infected patients, the most common extrapulmonary site is lymph mode followed by spleen.Key Words: Extrapulmonary TB, HIV Infection 相似文献37.
38.
AB Kimball U Gieler D Linder F Sampogna RB Warren M Augustin 《Journal of the European Academy of Dermatology and Venereology》2010,24(9):989-1004
Psoriasis is associated with significant physical and psychological burden affecting all facets of a patient’s life – relationships, social activities, work and emotional wellbeing. The cumulative effect of this disability may be self‐perpetuating social disconnection and failure to achieve a ‘full life potential’ in some patients. Health‐related quality of life studies have quantified the burden of psoriasis providing predominantly cross‐sectional data and point‐in‐time images of patients’ lives rather than assessing the possible cumulative disability over a patient’s lifetime. However, social and economic outcomes indicate there are likely negative impacts that accumulate over time. To capture the cumulative effect of psoriasis and its associated co‐morbidities and stigma over a patient’s life course, we propose the concept of ‘Cumulative Life Course Impairment’ (CLCI). CLCI results from an interaction between (A) the burden of stigmatization, and physical and psychological co‐morbidities and (B) coping strategies and external factors. Several key aspects of the CLCI concept are supported by data similar to that used in health‐related quality of life assessments. Future research should focus on (i) establishing key components of CLCI and determining the mechanisms of impairment through longitudinal or retrospective case–control studies, and (ii) assessing factors that put patients at increased risk of developing CLCI. In the future, this concept may lead to a better understanding of the overall impact of psoriasis, help identify more vulnerable patients, and facilitate more appropriate treatment decisions or earlier referrals. To our knowledge, this is a first attempt to apply and develop concepts from ‘Life Course Epidemiology’ to psoriasis research. 相似文献
39.
Musculoskeletal neoplasms after intraarterial chemotherapy: correlation of MR images with pathologic specimens 总被引:6,自引:0,他引:6
The most accurate prognostic indicator in patients with musculoskeletal sarcomas is the percentage of tumor necrosis after intraarterial chemotherapy. Magnetic resonance (MR) imaging was evaluated to determine its ability to indicate the percentage of necrosis in musculoskeletal neoplasms after treatment. Fourteen patients with musculoskeletal neoplasms underwent treatment protocols including intraarterial chemotherapy (n = 14), radiation therapy (n = 6), and systemic chemotherapy (n = 14). All patients underwent MR imaging before and after treatment, and all underwent either limb salvage surgery (n = 8) or amputation (n = 6) within 1 week of the last MR examination. Standard unehanced spin-echo T1-, spin-density-, and T2-weighted MR sequences were used. The MR images were compared with the pathologic specimens. On T2-weighted images, the signal intensities of viable tumor, tumor necrosis, edema, hemorrhage, and necrosis overlapped. With the unenhanced spin-echo technique, MR imaging cannot be used to predict the percentage of tumor necrosis in musculoskeletal neoplasms after intraarterial chemotherapy. 相似文献
40.
Percutaneous drainage of chest abscesses in children 总被引:1,自引:0,他引:1
Seven patients ranging in age from 3 to 18 years underwent percutaneous drainage of eight intrathoracic abscesses. Five of the abscesses were mediastinal or paramediastinal and resulted from esophageal perforation or esophageal anastomotic leakage. The abscesses resolved in each case, with a mean catheter drainage time of 28 days and no need for surgical intervention. Three of the abscesses were intrapulmonary, and each lay adjacent to a pleural surface. All three lung abscesses resolved within 19-24 days, without thoracotomy or wedge resection. 相似文献