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   17468篇
  免费   615篇
  国内免费   31篇
耳鼻咽喉   921篇
儿科学   520篇
妇产科学   1178篇
基础医学   2161篇
口腔科学   149篇
临床医学   960篇
内科学   3607篇
皮肤病学   251篇
神经病学   1907篇
特种医学   306篇
外科学   1290篇
综合类   38篇
一般理论   1篇
预防医学   1241篇
眼科学   562篇
药学   2437篇
中国医学   37篇
肿瘤学   548篇
  2023年   85篇
  2022年   60篇
  2021年   166篇
  2020年   144篇
  2019年   265篇
  2018年   583篇
  2017年   411篇
  2016年   426篇
  2015年   380篇
  2014年   621篇
  2013年   923篇
  2012年   1118篇
  2011年   1413篇
  2010年   709篇
  2009年   329篇
  2008年   886篇
  2007年   1244篇
  2006年   1325篇
  2005年   1266篇
  2004年   1320篇
  2003年   1314篇
  2002年   1070篇
  2001年   466篇
  2000年   512篇
  1999年   300篇
  1998年   105篇
  1997年   27篇
  1996年   20篇
  1995年   21篇
  1994年   14篇
  1993年   13篇
  1992年   19篇
  1991年   15篇
  1990年   38篇
  1989年   13篇
  1988年   21篇
  1987年   22篇
  1986年   26篇
  1985年   32篇
  1984年   22篇
  1983年   25篇
  1982年   23篇
  1981年   33篇
  1980年   23篇
  1979年   22篇
  1978年   25篇
  1977年   19篇
  1976年   15篇
  1975年   21篇
  1974年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Electroconvulsive therapy (ECT) as a medical procedure of higher risk as well as a therapy evoking certain controversies requires strict obedience to the conditions of acquiring the patient's informed consent to the offered method of treatment. To acquire the patient's consent it is necessary to inform him/her about the different aspects of electroconvulsive therapy. The paper stresses that in the case of ECT therapy, the spoken information given to the patient seems insufficient. It is necessary to work out a Polish questionnaire for acquiring the patient's consent to electroconvulsive therapy and to apply it in all psychiatric institutions that carry out ECT procedures.  相似文献   
992.
BACKGROUND: CD146 is a novel cell adhesion molecule localized at the endothelial junction. Its increased plasma levels in chronic renal failure are linked to endothelial dysfunction. Endothelial dysfunction and hemostatic disturbances, a common feature of nephrotic syndrome (NS), mimics a state of protein loosing by peritoneal membrane in patients on chronic ambulatory peritoneal dialyses (CAPD). The aim of the study was to assess CD146 in relation to other markers of endothelial cell injury in patients with NS in comparison to patients on CAPD. MATERIALS AND METHODS: We studied 45 CAPD patients, 43 patients with nephrotic syndrome and 25 healthy volunteers. Markers of endothelial cell injury: TFPI total, full length, truncated, von Willebrand factor, trombomodulin, P-selectin, E-selectin, ICAM, VCAM and CD146 were assessed using commercially available kits. RESULTS: All these markers studied except selectins were significantly elevated in patients with NS and CAPD when compared to the healthy volunteers. In CAPD, VCAM, thrombomodulin and CD146 were significantly elevated over NS patients. CD146 correlated significantly with ICAM as well as total and truncated TFPI in CAPD patients. Moreover, total TFPI was positively related to VCAM. CD146 correlated with ICAM in NS, whereas in healthy volunteers CD146 correlated only with TFPI concentration. CONCLUSIONS: Our studies indicate that in nephrotic patients, as well as in CAPD, there is an evidence of endothelial cell injury. Correlations between CD146 and adhesion molecules and TFPI might further support its use as a endothelial cell function marker.  相似文献   
993.
We examined the influence of CP 154,526, a selective antagonist of corticotropin-releasing factor (CRF)1 receptors, in the locomotor, sensitizing, discriminative stimulus and rewarding effects of cocaine, as well as on the cocaine-induced reinstatement of cocaine-seeking behavior in male Wistar rats. CP 154,526 in doses of 5, 10 and 20 mg/kg, which did not affect basal locomotor activity, dose-dependently reduced the hyperactivation evoked by cocaine. To assess the effects of CP 154,526 on the expression of cocaine sensitization, the rats were injected with either saline or cocaine (10 mg/kg) for 5 days, and were then challenged with cocaine (10 mg/kg) after pretreatment with saline or CP 154,526 on day 5 of withdrawal. The cocaine-induced hyperactivity in sensitized rats was reduced by CP 154,526 (10 and 20 mg/kg). In rats trained to discriminate cocaine (10 mg/kg) from saline, pretreatment with CP 154,526 (5-20 mg/kg) did not affect the cocaine (1.25-10 mg/kg)-induced discriminative stimulus effects. In a self-administration model, the rats were trained to self-administer cocaine (0.5 mg/kg/infusion) in the FR 5 schedule of reinforcement. Administration of CP 154,526 (10-20 mg/kg) did not alter the rewarding effects of cocaine, assessed as the number of active-lever presses and infusions; however, following a 10-day extinction phase, CP 154,526 (5-20 mg/kg) significantly decreased in a dose-dependent manner the cocaine (10 mg/kg) priming-induced reinstatement of cocaine-seeking behavior. The present study implies that CRF1 receptors control the expression of cocaine hyperactivation and sensitization as well as the cocaine-induced relapse behavior, but do not play any role in cocaine discrimination and self-administration. These findings may suggest that CRF1 receptor antagonists should be considered as possible medications in the treatment of cocaine addiction.  相似文献   
994.
The aim of the present study was to test the hypothesis that exposure of astrocytes depleted of glutathione (GSH) to simulated ischemia conditions in vitro and treated with immunosuppressant immunophilin ligands (cyclosporin A (CsA) and FK506) can increase intracellular GSH levels and that such mechanism may be responsible, at least in part, for their protective effects. In addition, we also compared the antioxidant properties of these immunosuppressants with N-acetylcysteine (NAC), a precursor of GSH synthesis. GSH depletion was induced by 24 h pretreatment with L-buthionine sulfoximine (BSO). Cultures of rat astrocytes were exposed to CsA (1-50 microM) and FK506 (1-1000 nM) and NAC (100 or 200 microM). We examined the effects of these compounds on apoptosis, cell viability, reactive oxygen species production and GSH content. Our study demonstrated that toxicity of simulated ischemia conditions were enhanced when intracellular GSH was depleted, and immunosuppressants (especially 100 nM FK506 and 10 microM CsA) effectively prevented ischemia toxicity in GSH depleted astrocytes. In addition, we have shown that interfering with the generation of GSH and attenuation, the rise of oxidative stress level by NAC may be a powerful tool for prevention of ischemia-induced glial cell damage.  相似文献   
995.
996.
997.
998.
INTRODUCTION: The aim of this study was to assess the changes affecting natural killer cytotoxic cell (NKCC) activity following intraperitoneal implantation of a double veloured polyester prosthesis in a rat model. MATERIAL/METHODS: Blood samples were taken by cardiac puncture 1 h before (base line) and 14, 28, 100 and 180 days post-implantation. Peripheral blood mononuclear cells were separated from heparinized blood by density centrifugation. A standard, 4 h (51)Cr-release assay against YAC-1 target cells at effector to target ratios of 12:1; 25:1 and 50:1 was performed and the number of total leukocytes, lymphocytes, granulocytes, monocytes, and large granular lymphocytes (LGLs), as well as serum corticosterone levels (radioimmunoassay method) were determined. RESULTS: Comparative analysis of the results obtained from animals with implants, baseline samples, and a control group (laparotomy only) revealed lower NKCC, LGL, leukocyte and lymphocyte counts and elevated plasma corticosterone levels in animals receiving the implant on the 14th day post-implantation. CONCLUSIONS: Our findings indicate that the polyester implant can transiently modulate immune system activities. Since NK cells are important in the control of viral infection and carcinogenesis in humans, it is possible that the stress generated by polyester prostheses can exacerbate the surgical stress and put patients at a higher risk for viral infection and/or metastases.  相似文献   
999.
OBJECTIVE: The aim of this study was to estimate safety and efficacy of Hasson technique in laparoscopic surgery. MATERIAL AND METHOD: In those patients where adhesions are suspected pneumoperitoneum was achieved by open Hasson technique. The time of this procedure, changes of hemoglobin concentration, duration of hospitalization and postoperative pain was compared with those cases where pneumoperitoneum was performed by blind insertion of the Veress needle. RESULTS AND CONCLUSIONS: Hasson technique is more time consuming procedure but its safety and efficacy is significantly higher in those patients where adhesions are suspected.  相似文献   
1000.
OBJECTIVES AND DESIGN: Neutrophils play important role in first line defence an they release soluble growth and chemotactic factors and guide the recruitment of non-specific immune effector cells. We estimated the activity and ability to reduce of nitroblue tetrazolium (NBT) by peripheral blood neutrophils in women with benign or malignant ovarian tumours. MATERIALS AND METHODS: The study was performed on 43 women between the ages of 19 and 72 with ovarian tumours. Cystadenoma serosum was diagnosed in 19 women, Cystadenocarcinoma serosum in 9, and teratoma adultum in 15 women. Venous blood samples were obtained prior to the operation. The control group consisted of 30 women their age range was from 22 to 60 years. In peripheral blood samples from both groups; there leukocyte counts and total neutrophils were determined. Metabolic activity was investigated by nitroblue tetrazolium reduction spontaneous (NBTsp) test, and stimulation by latexs (NBTst) test. RESULTS: In women with ovarian tumours, the index of spontaneous NBT reduction turned out to be significantly higher than that in the control group (p<0.0001). In the group studied, the index of latex-stimulated NBT reduction was significantly lower than that in the control group (p<0.0001). CONCLUSIONS: Intensity oxidation-reduction changes of neutrophils in reduction NBT in women with ovarian tumours were observed.  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