首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2776篇
  免费   199篇
  国内免费   16篇
医药卫生   2991篇
  2022年   12篇
  2021年   43篇
  2020年   14篇
  2019年   51篇
  2018年   65篇
  2017年   42篇
  2016年   28篇
  2015年   39篇
  2014年   58篇
  2013年   87篇
  2012年   132篇
  2011年   145篇
  2010年   111篇
  2009年   88篇
  2008年   101篇
  2007年   112篇
  2006年   129篇
  2005年   115篇
  2004年   125篇
  2003年   101篇
  2002年   98篇
  2001年   97篇
  2000年   97篇
  1999年   98篇
  1998年   58篇
  1997年   44篇
  1996年   45篇
  1995年   43篇
  1994年   32篇
  1993年   30篇
  1992年   83篇
  1991年   68篇
  1990年   60篇
  1989年   64篇
  1988年   49篇
  1987年   55篇
  1986年   50篇
  1985年   45篇
  1984年   31篇
  1983年   37篇
  1982年   14篇
  1981年   12篇
  1980年   12篇
  1979年   22篇
  1978年   12篇
  1977年   16篇
  1975年   10篇
  1974年   14篇
  1973年   14篇
  1969年   10篇
排序方式: 共有2991条查询结果,搜索用时 312 毫秒
1.
BackgroundCervical spondylodiscitis is a rare but severe complication of pharyngeal surgery.Material and methodsThis multicenter retrospective study reported all patients in the database of the French head and neck tumor study group (GETTEC) affected by cervical spondylodiscitis after transoral robotic surgery (TORS) for malignant pharyngeal tumor from January 2010 to January 2017.ObjectivesTo describe cases of post-TORS cervical spondylodiscitis, identify alarm signs, and determine optimal management of these potentially lethal complications.ResultsSeven patients from 6 centers were included. Carcinomas were located in the posterior pharyngeal wall. Tumor stage was T1 or T2. All patients had risk factors for spondylodiscitis. Mean time to diagnosis was 12.6 days. The interval between surgery and spondylodiscitis diagnosis ranged from 20 days to 4.5 months, for a mean 2.1 months. The most common symptom was neck pain (87%). Infections were polymicrobial; micro-organisms were isolated in 5 cases and managed by intravenous antibiotics, associated to medullary decompression surgery in 3 cases. Follow-up found favorable progression in 4 cases, and 3 deaths (mortality, 43%).ConclusionThis French multicenter study found elevated mortality in post-TORS spondylodiscitis, even in case of limited resection. Surgeons must be aware of this complication and alerted by persistent neck pain, fever, asthenia, impaired or delayed posterior pharyngeal wall wound healing or elevation of inflammatory markers. MRI is the most effective diagnostic radiological examination.  相似文献   
2.
Platelet antibodies in systemic lupus erythematosus   总被引:2,自引:0,他引:2  
In systemic lupus erythematosus (SLE), the precise cause of the thrombocytopenia is unknown. Since platelet associated IgG is increased in many patients, it has been suggested that the destruction of platelets might be dependent on specific antibodies. In nine patients with SLE, platelet associated immunoglobulins were found together with free serum antibody which bound to platelets from all normal subjects. Using an immunoblotting technique with membrane proteins from normal platelets incubated with patient sera, target antigens were localized on a band of mol wt 108,000 in two cases (B. and N.) and on a band of mol wt 66,000 in a third (M.). When the same technique was applied to autologous platelets of patient N., autoantibody binding to the protein of mol wt 108,000 was demonstrated. The antigenic determinants were not removed from the platelets by enzyme treatment or by disulphide bond reduction, and were localized in the cytoplasmic fraction of the platelets.  相似文献   
3.
Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.  相似文献   
4.
5.
The effects of OSM on proliferation and differentiation of osteosarcoma and nontransformed osteoblasts were analyzed. OSM downregulates osteoblast markers but induces the glial fibrillary acidic protein by the combined activation of PKCdelta and STAT3, offering new lines of therapeutic investigations. INTRODUCTION: Oncostatin M (OSM) is a multifunctional cytokine of the interleukin-6 family implicated in embryonic development, differentiation, inflammation, and regeneration of various tissues, mainly the liver, bone, and the central nervous and hematopoietic systems. One particularity of OSM relies on its growth inhibitory and pro-differentiating effects on a variety of tumor cell lines such as melanoma, providing arguments for a therapeutic application of OSM. The objective of this study was to analyze the effects of OSM on osteosarcoma cell lines proliferation and differentiation. MATERIALS AND METHODS: Proliferation was analyzed by 3H thymidine incorporation. Differentiation was analyzed by semiquantitative RT-PCR and immunocytochemistry for various markers. Alizarin red S staining was used to evaluate bone nodule formation. Morphological changes were studied by confocal and electron microscopy. Western blotting, kinases inhibitors, and dominant negative STAT3 were used to identified the signaling pathways implicated. RESULTS: OSM inhibits the growth of rat osteosarcoma cell lines as well as normal osteoblasts, in correlation with induction of the cyclin-dependent kinases inhibitor p21WAF1. However, OSM reduces osteoblast markers such as alkaline phosphatase, osteocalcin, and bone sialoprotein, leading to strong inhibition of mineralized nodule formation. This inhibitory effect is restricted to mature osteoblasts and differentiated osteosarcoma because OSM effectively stimulates osteoblast markers and bone nodule formation in early, but not late, bone marrow mesenchymal stem cell (BMSC) cultures. In osteosarcoma cells or BMSC, OSM induces expression of the glial fibrillary acidic protein (GFAP) as well as morphological and ultrastructural changes, for example, elongated shape and bundles of microfilaments in cell processes. Rottlerin (PKCdelta inhibitor), and to a lesser degree UO126 (MEK/ERK inhibitor), prevents the loss of osteoblastic markers by OSM, whereas dominant negative STAT3 prevents GFAP induction. CONCLUSIONS: These results highlight the particular gene expression profile of OSM-treated osteosarcoma cells and BMSCs, suggesting either a osteocytic or a glial-like phenotype. Together with the implication of PKCdelta, ERK1/2, and STAT3, these results offer new lines of investigations for neural cell transplantation and osteosarcoma therapy.  相似文献   
6.
One hundred forty five individuals who sought medical attention as a result of a motor vehicle accident (MVA), and who were initially assessed 1 to 4 months post-MVA, were followed up prospectively for 6 months to determine how many of the 55 with posttraumatic stress disorder (PTSD) and the 43 with sub-syndromal PTSD would remit and what variables would predict remission. Thirty (55%) of those with initial PTSD had remitted at least in part by 6 months while 67% of those with sub-syndromal PTSD had remitted (and 5% had worsened). Four variables, including severity of initial symptoms, degree of initial physical injury, relative degree of physical recovery by 4 months and whether a close family member suffered a trauma during the follow-up interval, combined to classify 6-month clinical status of 84% of those with initial PTSD secondary to MVAs.  相似文献   
7.
Gallbladder anomalies are rare and normally affect its shape, size, and position. We report on a 3-year-old boy with a gallbladder divided transversally by a windsock-type diaphragm, isolating the fundus from the rest of the biliary tree. Bilobed and multiseptated gallbladder have been described before, but this is the first isolated case of a congenital hourglass gallbladder.  相似文献   
8.
The Kasabach-Merritt syndrome is characterized by thrombocytopenia and localized coagulopathy associated with a hemangioma. Most techniques applied to eradicate the tumor or accelerate its involution (surgery, radiation therapy, embolization) are invasive and require transfusion of large amounts of blood products. In some cases, medical treatment is the only alternative. Efficacy of steroids and antifibronolytic agents has already been described, but even this approach is associated with the administration of blood products. We report two cases of infants with Kasabach-Merritt syndrome associated with cardiac and hepatic hemangiomas. At admission, both had signs of cardiac failure. They were successfully treated with prednisone and epsilon-aminocaproic acid (EACA). Blood products were not required once the diagnosis was made. These observations have important implications for the management of patients with Kasabach-Merritt syndrome because they show that even in severe cases blood transfusions can be avoided by the use of prednisone and EACA.  相似文献   
9.
10.
The Proxemics/Activity test and the Eat/Drink test, two components of the Anxiety/Defense Test Battery, were developed to measure defensive reactions to situations associated with a natural predator (cat). In the present studies the behavioral effects of 8-OH-DPAT treatment (0.01–1.0 mg/kg, SC) were entirely consistent with anxiety/fear reduction. These effects included an increase in time spent near the cat compartment, and a complimentary decrease in time spent farthest from this compartment, together with an increase in transits and locomote behavior. 8-OH-DPAT (1.0 mg/kg) also increased eat frequencies and durations (highly preferred food) both during and following cat presentation, without influencing drinking. This finding is discussed with reference to previous findings with 8-OH-DPAT in studies assessing both food intake and anxiolysis. Interestingly, 8-OH-DPAT was more potent in a majority of its effects in female subjects, a finding consistent with recent neurochemical data. These findings provide important behavioral evidence for a sexual differentiation in 5-HT function, and support the case for greater emphasis on female subjects in animal models of anxiety.Supported by NIH MH42803 and RCMI Grants RR03061 and RR01825  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号