首页 | 本学科首页   官方微博 | 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   5145篇
  免费   304篇
  国内免费   17篇
耳鼻咽喉   58篇
儿科学   139篇
妇产科学   96篇
基础医学   721篇
口腔科学   118篇
临床医学   400篇
内科学   1246篇
皮肤病学   149篇
神经病学   421篇
特种医学   250篇
外科学   661篇
综合类   11篇
一般理论   1篇
预防医学   244篇
眼科学   60篇
药学   415篇
中国医学   4篇
肿瘤学   472篇
  2023年   32篇
  2022年   58篇
  2021年   78篇
  2020年   60篇
  2019年   84篇
  2018年   100篇
  2017年   90篇
  2016年   99篇
  2015年   100篇
  2014年   140篇
  2013年   157篇
  2012年   303篇
  2011年   345篇
  2010年   207篇
  2009年   172篇
  2008年   302篇
  2007年   340篇
  2006年   309篇
  2005年   334篇
  2004年   258篇
  2003年   285篇
  2002年   269篇
  2001年   84篇
  2000年   105篇
  1999年   98篇
  1998年   83篇
  1997年   50篇
  1996年   50篇
  1995年   39篇
  1994年   31篇
  1993年   39篇
  1992年   69篇
  1991年   58篇
  1990年   63篇
  1989年   48篇
  1988年   31篇
  1987年   42篇
  1986年   37篇
  1985年   47篇
  1984年   51篇
  1983年   40篇
  1982年   21篇
  1981年   24篇
  1980年   25篇
  1979年   28篇
  1978年   32篇
  1977年   22篇
  1974年   15篇
  1973年   14篇
  1970年   12篇
排序方式: 共有5466条查询结果,搜索用时 140 毫秒
71.
The anti-amnesic effects of dynorphins on beta-amyloid peptide-(25-35)-induced impairment of learning and/or memory in mice were investigated using a Y-maze task and a passive avoidance test. Administration of beta-amyloid peptide-(25-35) (betaAP(25-35); 8.2 nmol, i.c.v.) 7 and 14 days before behavioral tests induced a decrease in both alternation behavior and latency in passive avoidance tests. Dynorphin A-(1-13) and A-(2-13) (0.5 and/or 1.5 nmol, i.c.v.) 30 min before behavioral tests improved the beta-amyloid peptide-(25-35)-induced impairment of alternation performance and shortened the step-down latency. Nor-binaltorphimine (4.9 nmol, i.c.v.) partially blocked the effects of dynorphin A-(1-13), but not A-(2-13). These results indicate that dynorphin A-(1-13) and A-(2-13) improve amnesia induced by betaAP-(25-35) via not only kappa opioid receptors, but also by non-opioid mechanisms.  相似文献   
72.
BACKGROUND: Sevoflurane reportedly inhibits adenosine diphosphate-induced platelet aggregation by suppressing thromboxane A2 formation. The increase in intracellular calcium concentration that fosters platelet aggregation, however, is also induced by other cell signaling pathways, such as activation of the production of inositol 1,4,5-triphosphate by thrombin. The current study aimed to clarify the net influence of sevoflurane on thrombin-induced platelet aggregation. METHODS: Washed platelets were stimulated by thrombin after incubation with 0.5, 1.0, or 1.5 mM sevoflurane, halothane, or isoflurane. Aggregation curves were measured by an aggregometer. Intracellular calcium concentration was measured fluorometrically using fura-2. Calcium mobilization via plasma membrane calcium channels and the dense tubular system was assessed differentially. Intracellular inositol 1,4,5-triphosphate was measured by radioimmunoassay. RESULTS: Halothane significantly suppressed aggregation ratios at 5 min compared with those in controls (89 +/- 7%) to 71 +/- 10% (1.0 mM) and 60 +/- 11% (1.5 mM) and the increase in intracellular calcium concentration (controls, 821 +/- 95 nM vs. 440 +/- 124 nM [1.0 mM] or 410 +/- 74 nM [1.5 mM]). Halothane also significantly inhibited release of calcium from the dense tubular system (controls, 220 +/- 48 nM vs. 142 +/- 31 nM [1.0 mM]). Neither sevoflurane nor isoflurane produced a net change in aggregation ratios, intracellular calcium concentration, or calcium mobilization. Halothane (1 mM) significantly suppressed inositol 1,4,5-triphosphate concentrations, whereas neither 1 mM isoflurane nor 1 mM sevoflurane had any effect. CONCLUSIONS: Although sevoflurane has been reported to inhibit human platelet aggregation induced by weak agonists such as adenosine diphosphate, it does not inhibit human platelet aggregation induced by strong agonists such as thrombin.  相似文献   
73.
PURPOSE: Galectin-9, a member of the beta-galactoside-binding galectin family, induces aggregation of certain cell types. We assessed the contribution of galectin-9 to the aggregation of breast cancer cells as well as the relation between galectin-9 expression in tumor tissue and distant metastasis in patients with breast cancer. EXPERIMENTAL DESIGN: Subclones of MCF-7 breast cancer cells with high or low levels of galectin-9 expression were established and either cultured on plastic dishes or transplanted into nude mice. The tumors of 84 patients with breast cancer were tested for galectin-9 expression by immunohistochemistry. The patients were followed up for 14 years. RESULTS: MCF-7 subclones with a high level of galectin-9 expression formed tight clusters during proliferation in vitro, whereas a subclone (K10) with the lowest level of galectin-9 expression did not. However, K10 cells stably transfected with a galectin-9 expression vector aggregated in culture and in nude mice. Ectopic expression of galectin-9 also reduced MCF-7 cell adhesion to extracellular matrix proteins. Tumors of 42 of the 84 patients were galectin-9 positive, and those of 19 of the 21 patients with distant metastasis were galectin-9 negative. None of the 13 patients with galectin-9-positive tumors and lymph node metastasis up to level II manifested distant metastasis. The cumulative disease-free survival ratio for galectin-9-positive patients was more favorable than that for the galectin-9-negative group (P < 0.0001). Multivariate analysis revealed that galectin-9 status influenced distant metastasis independently of and to a greater extent than lymph node metastasis. CONCLUSIONS: Galectin-9 is a possible prognostic factor with antimetastatic potential in breast cancer.  相似文献   
74.
Nasal carriage of MRSA is a significant risk-factor for the endogenous MRSA infection in immunocompromised patients. MRSA infection in ICU patients is thus mostly endogenous infection. To evaluate the impact of mupirocin use on the incidence of endogenous infection caused by MRSA in an intensive care unit, we prospectively treated all patients in the unit with mupirocin, 3 times daily for 3 days. This routine use of mupirocin led to eradication of nasal MRSA carriage in 81.8% of surveillance cultures and to a significant reduction in the total incidence of MRSA infection among MRSA carrier patients (0 episode in 11 patients) when compared to historical controls prior to the use of mupirocin (3 episodes in 7 patients). Mupirocin nasal ointment was significantly effective to prevent endogenous MRSA infection.  相似文献   
75.
76.
77.
78.
We report a 38‐year‐old male patient who presented with cutaneous lesions mimicking widespread discoid lupus erythematosus with high‐grade fever, arthralgia and lymphadenopathy. Additional lymph node and skin biopsies, however, revealed karyorrhectic debris without neutrophils and numerous CD68‐positive cells, a characteristic finding of Kikuchi's disease (KD). Comparing skin biopsies on different occasions, we could see different forms of histopathology. The histopathology of skin lesions of KD may vary during the clinical course, which may reflect the stage of the disease.  相似文献   
79.
Objectives: To examine the association between Fcγ receptor (FcγR) polymorphisms and the development of hypersensitivity reactions to adalimumab in patients with rheumatoid arthritis.

Methods: Sixty-five patients receiving adalimumab were enrolled in the study. Genetic polymorphisms for FcγR3B were genotyped in FCGR3B NA1/2 alleles by real allelic discrimination assay. Clinical information and the occurrence of a hypersensitivity reaction to adalimumab were collected from the patients’ charts.

Results: A hypersensitivity reaction was observed in 12% of the patients. Clinical information obtained from patients with a reaction and those without were the same. The FCGR3B NA1/NA1, NA1/NA2, and NA2/NA2 alleles were found in 75%, 13%, and 13% of the patients with hypersensitivity reaction, respectively, and in 28%, 42%, and 30% of those without a hypersensitivity reaction, respectively (p?=?0.04). Multivariate logistic regression analysis identified only the NA1/NA1 as an independent relevant factor for a hypersensitivity reaction to adalimumab (OR 7.7, p?=?0.01).

Conclusions: The FCGR3B NA1/NA1 genotype is associated with hypersensitivity reactions to adalimumab.  相似文献   
80.
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