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   130132篇
  免费   8688篇
  国内免费   2355篇
耳鼻咽喉   1660篇
儿科学   3091篇
妇产科学   4199篇
基础医学   19529篇
口腔科学   3773篇
临床医学   10761篇
内科学   23028篇
皮肤病学   2536篇
神经病学   8454篇
特种医学   4410篇
外国民族医学   6篇
外科学   18002篇
综合类   7486篇
现状与发展   2篇
一般理论   35篇
预防医学   9780篇
眼科学   3104篇
药学   11717篇
  8篇
中国医学   1848篇
肿瘤学   7746篇
  2021年   1634篇
  2020年   1115篇
  2019年   1518篇
  2018年   2068篇
  2017年   1598篇
  2016年   1598篇
  2015年   1978篇
  2014年   2530篇
  2013年   3112篇
  2012年   4399篇
  2011年   4725篇
  2010年   2935篇
  2009年   2591篇
  2008年   4003篇
  2007年   4174篇
  2006年   4129篇
  2005年   3687篇
  2004年   3406篇
  2003年   3309篇
  2002年   3121篇
  2001年   7129篇
  2000年   7214篇
  1999年   5907篇
  1998年   1959篇
  1997年   1507篇
  1996年   1018篇
  1995年   924篇
  1992年   3774篇
  1991年   3860篇
  1990年   3587篇
  1989年   3580篇
  1988年   3445篇
  1987年   3302篇
  1986年   3103篇
  1985年   2980篇
  1984年   2055篇
  1983年   1797篇
  1982年   986篇
  1979年   1912篇
  1978年   1184篇
  1977年   987篇
  1976年   918篇
  1975年   1191篇
  1974年   1361篇
  1973年   1414篇
  1972年   1358篇
  1971年   1248篇
  1970年   1138篇
  1969年   1121篇
  1968年   1026篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The 2.0-Å resolution x-ray crystal structure of a novel trimeric antibody fragment, a “triabody,” has been determined. The trimer is made up of polypeptides constructed in a manner identical to that previously described for some “diabodies”: a VL domain directly fused to the C terminus of a VH domain—i.e., without any linker sequence. The trimer has three Fv heads with the polypeptides arranged in a cyclic, head-to-tail fashion. For the particular structure reported here, the polypeptide was constructed with a VH domain from one antibody fused to the VL domain from an unrelated antibody giving rise to “combinatorial” Fvs upon formation of the trimer. The structure shows that the exchange of the VL domain from antibody B1-8, a Vλ domain, with the VL domain from antibody NQ11, a Vκ domain, leads to a dramatic conformational change in the VH CDR3 loop of antibody B1-8. The magnitude of this change is similar to the largest of the conformational changes observed in antibody fragments in response to antigen binding. Combinatorial pairing of VH and VL domains constitutes a major component of antibody diversity. Conformationally flexible antigen-binding sites capable of adapting to the specific CDR3 loop context created upon VH–VL pairing may be employed by the immune system to maximize the structural diversity of the immune response.  相似文献   
62.
63.
Physical therapy without anesthesia or plaster casts was used to treat 338 cases of clubfoot (CF). Our technique is based on progressive sequential manipulations at birth. We first reduce the varus and later the equinus component of the CF. The gentle stretches used in this technique are complemented by active physiotherapy stimulating the muscles, and then a simple splint is suited to the foot to fix its degree of realignment. When used alone, this technique achieves 77% good and fair results. In resistant cases, complementary surgery was used. We obtained 96% good and fair results.  相似文献   
64.
Effects of the MAO-A-inhibitor brofaromine (BRO), 10 mg/kg po after repeated (twice daily for 14 days) administration on the spontaneous behavior (exploratory and basal locomotor activities) and the exploratory activity modified by methoxamine, clonidine and d-amphetamine in male Wistar rats were studied in both light and dark phases of a diurnal cycle (L: 0700-1900 h). After single administration BRO in the light phase had no effects. In the dark phase BRO decreased the exploration (62% of control, p less than 0.01), increased the clonidine-evoked hypoactivity and amphetamine-evoked hyperactivity. The L-D differences occurred also after repeated administration. BRO in the light phase did not influence the exploration, decreased basal locomotor activity, did not change methoxamine and clonidine action and potentiated the action of amphetamine. In the dark phase, however, it did not influence the exploration and basal locomotor activity, intensified the methoxamine effect, and did not change the clonidine and amphetamine actions. The results demonstrate that the effects of BRO on behavior in rats: 1) differ from the effects caused by other antidepressants which are not MAO inhibitors; 2) are phase-dependent after both single and repeated administration.  相似文献   
65.
M Y Fan  Z P Lum  X W Fu  L Levesque  I T Tai  A M Sun 《Diabetes》1990,39(4):519-522
Prolonged survival of pancreatic islet allografts implanted in diabetic BB rats was achieved by encapsulation of individual islets in a protective biocompatible alginate-polylysine-alginate membrane without immunosuppression. Intraperitoneal transplantation of the encapsulated islets reversed the diabetic state of the recipients within 3 days and maintained normoglycemia for 190 days. Normal body weight and urine volume were maintained during this period, and no cataracts were detected in the transplant recipients. In contrast, control rats receiving transplants of unencapsulated islets experienced normoglycemia for less than 2 wk. These results demonstrated that microencapsulation can protect allografted islets from both graft rejection and autoimmune destruction without immunosuppression in an animal model that mimics human insulin-dependent diabetes.  相似文献   
66.
67.
68.
The present authors investigated the excretion, distribution and pharmacokinetics of the novel potential antirheumatic agent flobufen and its active metabolite after p.o. and i.v. doses of 2, 10 and 50 mg/kg administered to rats. The drug is resorbed well from the digestive tract and mostly it is metabolized to the principal metabolite M, which is only slowly excreted from the organism mainly by renal clearance. Within the whole dose range the kinetics of the drug is linear. Binding of flobufen and M to proteins is high (95-99%). The highest concentrations of radioactive metabolites (mostly M) were found in the plasma, liver, lungs, kidneys, connective tissue and inflammatory foci. The penetration of metabolites through the placenta and excretion in human milk are relatively important.  相似文献   
69.
70.
The clinical, radiologic, and histopathologic findings of a case of bilateral dacryops is reported in a 49-year-old man. The patient presented with cystic masses located in superior lateral orbits and underwent bilateral excisions of these without any postoperative complications.  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