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   74218篇
  免费   7809篇
  国内免费   4652篇
耳鼻咽喉   640篇
儿科学   1188篇
妇产科学   536篇
基础医学   6589篇
口腔科学   1162篇
临床医学   9612篇
内科学   9126篇
皮肤病学   788篇
神经病学   2922篇
特种医学   2695篇
外国民族医学   29篇
外科学   6754篇
综合类   16268篇
现状与发展   18篇
一般理论   11篇
预防医学   7352篇
眼科学   1751篇
药学   8286篇
  112篇
中国医学   5852篇
肿瘤学   4988篇
  2024年   330篇
  2023年   1113篇
  2022年   2738篇
  2021年   3523篇
  2020年   2892篇
  2019年   2230篇
  2018年   2196篇
  2017年   2519篇
  2016年   2265篇
  2015年   3397篇
  2014年   4423篇
  2013年   4716篇
  2012年   6477篇
  2011年   6983篇
  2010年   5553篇
  2009年   4580篇
  2008年   4916篇
  2007年   4823篇
  2006年   4399篇
  2005年   3725篇
  2004年   2699篇
  2003年   2524篇
  2002年   2128篇
  2001年   1605篇
  2000年   1108篇
  1999年   698篇
  1998年   350篇
  1997年   379篇
  1996年   258篇
  1995年   203篇
  1994年   161篇
  1993年   119篇
  1992年   98篇
  1991年   87篇
  1990年   83篇
  1989年   83篇
  1988年   45篇
  1987年   46篇
  1986年   37篇
  1985年   34篇
  1984年   18篇
  1983年   21篇
  1982年   12篇
  1981年   11篇
  1980年   7篇
  1979年   18篇
  1978年   10篇
  1977年   10篇
  1976年   5篇
  1975年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
【目的】研究拉米夫定对HBsAg阳性孕妇的乙肝病毒 (HBV)宫内阻断作用。【方法】拉米夫定组 43例 ,孕 2 8周起口服拉米夫定 ,每天 10 0mg至产后 30d。对照组 5 2例 ,未予用药。两组孕妇均于孕 2 8周、分娩前 ,其新生儿于生后 2 4h内免疫接种前抽静脉血检测HBsAg、HBeAg及HBV的定量。【结果】拉米夫定组孕妇HBV的DNA水平显著下降 (P <0 0 5 ) ,其新生儿宫内感染率 (16 3% )明显低于对照组 (32 7% ) ,P <0 0 5。两组孕妇及其新生儿未发现有不良反应。【结论】携带HBV孕妇产前服用拉米夫定可有效减少HBV宫内感染发生率。  相似文献   
73.
环孢素A治疗难治性肾病综合征的临床观察   总被引:1,自引:0,他引:1  
目的 :研究环孢素A(CsA)治疗原发性难治性肾病综合征的疗效及安全性。方法 :2 1例患者均行肾活检检查 ,其中系膜增殖性肾小球肾炎 (MsPGN) 13例 ,膜性肾病 (MN) 6例 ,膜增殖性肾小球肾炎 (MPGN) 2例。采用皮质激素和CsA联合治疗 ;CsA初始剂量 5mg·kg-1·d-1,3个月后适当减量 ,疗程 1年以上。强的松开始剂量 1mg·kg-1·d-1,8周后逐渐减量 ,疗程也在 1年以上。结果 :CsA联合皮质激素 ,使系膜增殖性肾小球肾炎和膜性肾病患者蛋白定量下降 ,血清白蛋白上升 (P<0 .0 1)。 13例系膜增殖性病变患者中 4例在第 4周起效 ,11例获完全缓解。 6例MN患者中 ,3例第 8周见效 ,4例获完全缓解 ,1例部分缓解 ,1例无效。膜增殖性肾炎患者 1例部分缓解 ,1例无效。治疗前后肾功能无变化。结论 :CsA是治疗难治性肾病综合征有效的免疫抑制剂 ,对于CsA的适应症、治疗时间及长期应用的安全性还需进一步研究  相似文献   
74.
反映肾脏浓缩稀释功能的最佳指标——血、尿渗透量   总被引:2,自引:0,他引:2  
介绍渗透量的临床应用及其与尿比重的对比  相似文献   
75.
Between March 1984 and February 1991, six orthotopic liver transplantations were performed at the Chang Gung Memorial Hospital in Taiwan. The indications for transplantation were Wilson's disease (5 patients) and biliary atresia (1 patient). Donors and recipients were matched only for size and ABO blood group compatibility, and the recipient operations were performed without the use of a venovenous bypass. Arterial reconstruction was carried out by end-to-end hepatic artery anastomosis (4), thoracic aortic conduit (1), or interposition of an iliac artery graft (1), whereas biliary reconstruction was accomplished by a choledochocholedochostomy using a T-tube stent (4) or a choledochocholedochostomy using an external cholecystostomy without stenting (2). Biliary complications occurred in three patients, and all required additional surgery. The average duration of donor-liver cold ischemia, operating time, and blood loss during surgery were 7 h and 50 min (range, 4.5–9 h), 13.5 h (range, 11.8–17h), and 4,385 ml (range, 750–12,000 ml) respectively. The immunosuppressive regimens included a cyclosporinsteroid combination (n=2) and a triple-drug combination (n=4). All except one of the surviving patients experienced at least one rejection episode that was reversed by a methyl-prednisolone bolus and/or recycle. One patient developed a primary cytomegalovirus (CMV) infection that responded well to Ganciclovir treatment. Two of the patients died, one of injuries sustained in a traffic accident 3 years after transplantation, and the other of massive upper gastrointestinal bleeding. The overall survival value at 3 months was 83%, and the follow-up period ranged from 3 months to 7 years. All of the survivors have achieved complete rehabilitation and currently enjoy an excellent quality of life with normal liver function. Althought the present study involved a small number of cases, our results indicate that liver transplantation can be successfully achieved in a high proportion of patients with acceptable morbidity, mortality, and cost in an Asian setting. The extreme shortage of donor organs is currently the most important obstacle limiting the application of liver transplantation in Taiwan.Presented at The Second International Symposium on Treatment of Liver Cancer. Taipei, 3–4 February 1991  相似文献   
76.
Human renin is synthesized as an inactive zymogen (prorenin) which is processed to the active form. We synthesized an 11-amino acid peptide which spans the human prorenin processing site in order to develop a simple assay to study human prorenin activation. Six enzymes which are capable of activating recombinant prorenin in vitro were studied. Four of these enzymes digested the synthetic peptide in a specific fashion, as analyzed by reverse-phase high-performance liquid chromatography. Amino acid analysis of the purified digestion products revealed that trypsin cleaves between Arg-Leu, the authentic processing site, while kallikrein, plasmin and elastase all cleaved at alternate sites. On the other hand, pepsin and cathepsin D did not cleave this substrate, suggesting that the activation of prorenin by these proteases might occur at a site distinct from the authentic processing site. Our data suggest that this synthetic peptide may be used as a simple and specific assay for prorenin activation.  相似文献   
77.
Objective: To study the relationship between transaldolase activity, protein expression and testosterone synthesis in Leydig cells of pubertal mice. Methods: Leydig cells were cultured for 2 hours and 8 hours, to the Stimulation Group, hCG was added and to the Controls, only the vehicle. The testosterone concentration was then determined by enzyme-linked immunoadsordent assay (ELISA) and the transaldolase activity and protein expression by Western blot. Results: (1) Both the testosterone concentration and the transaldolase activity in both Stimulation Groups were significantly higher than those in the corresponding Controls (2 h: p<0.05-0.01; 8 h: P<0.001); (2) The ratios of the A isoform, the B isoform and the total transaldolase protein to β-actin between the Stimulation and Control Groups did not differ signifi-cantly. Conclusion: hCG stimulates the transaldolase activity as well as the testosterone synthesis in the Leydig cells of pubertal mice, indicating a positive relationship between them.  相似文献   
78.
Summary Effects of Chinese Medicinal Preparation “Re Du Qing” (RDQ) on the activation, proliferation and membrane fluidity of T lymphocytes from human peripheral blood Were studied by means of3H-TdR incorporation and DPH fluorescence polarization. The results showed that “RDQ” can:1) significantly inhibit the activation of T lymphocytes; 2) restrain the proliferation of activated T lymphoblasts in the presence of exogenous interleukin-2 (IL-2); and 3) increase the membrane fluidity of T lymphocytes and antagonize the decreased fluidity of lymphocyte membrane mediated by Con A or PHA. The functional abnormalities of T lymphocytes in some autoimmune diseases such as arthritis and the usefulness of RDQ in the treatment of these diseases were also discussed.  相似文献   
79.
It is documented that alkaline phosphatase (AP) plays an important role in bone mineralization. Considering that TN-AP is expressed in periodontal ligament fibroblasts, renal epithelial cells, and vascular endothelial cells, and that TN-AP is both a calcium-/phosphate-binding protein and a phosphohydrolytic enzyme, we hypothesize that membrane-bound AP also plays an important role in the initiation of physiological and pathological mineralizations in tissues other than bone and cartilage. To test this hypothesis, nonosteoblast cell lines, including a fibroblast line, a renal epithelial line, and a capillary endothelial line, were stably transfected to express high levels of rat bone AP on their cell surfaces. These rat bone AP-expressing cells were then cultured on filter membranes in the presence or absence of β-glycerol phosphate. von Kossa staining for calcium phosphate and transmission electron microscopy with electron diffraction analysis for minerals were employed to investigate the effect of membrane AP on extracellular calcium phosphate mineralization. Our results indicated that AP expression on these nonosteoblast-like cell surfaces have induced extracellular hydroxyapatite (HAP) mineralization. Our findings support the concept that membrane-bound AP contributes to extracellular apatitic mineralization by mechanisms that do not necessarily involve its hydrolase activity. They also suggest that AP might be important for the initiation of pathological mineralization in nonosteogenic tissues. Received: 11 January 1996 / Accepted: 31 October 1996  相似文献   
80.
手术联合中药治疗激素性股骨头缺血性坏死的实验研究   总被引:5,自引:0,他引:5  
目的 :初步探讨激素性股骨头缺血性坏死的发病机制 ,观察手术 +中药治疗本病的疗效。方法 :通过对新西兰大白兔联合应用马血清 +甲基强的松龙造模及手术处理 ,对正常组、模型组、手术组、手术 +中药组实验兔的血脂、血液流变学、血生化及股骨头标本切片观察 ,分析比较。结果 :手术 +中药治疗本病的疗效优于单纯保髋手术。结论 :手术 +活血化瘀补肾壮骨方法是股骨头缺血性坏死治疗的合理方法  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