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   30084篇
  免费   2148篇
  国内免费   114篇
耳鼻咽喉   579篇
儿科学   1239篇
妇产科学   441篇
基础医学   3073篇
口腔科学   720篇
临床医学   2690篇
内科学   6739篇
皮肤病学   610篇
神经病学   1777篇
特种医学   1271篇
外国民族医学   1篇
外科学   5502篇
综合类   530篇
一般理论   16篇
预防医学   1430篇
眼科学   1107篇
药学   2430篇
中国医学   63篇
肿瘤学   2128篇
  2023年   264篇
  2022年   500篇
  2021年   1222篇
  2020年   589篇
  2019年   959篇
  2018年   1126篇
  2017年   745篇
  2016年   801篇
  2015年   863篇
  2014年   1274篇
  2013年   1491篇
  2012年   2245篇
  2011年   2204篇
  2010年   1157篇
  2009年   1038篇
  2008年   1678篇
  2007年   1658篇
  2006年   1463篇
  2005年   1278篇
  2004年   1171篇
  2003年   1007篇
  2002年   867篇
  2001年   695篇
  2000年   639篇
  1999年   574篇
  1998年   215篇
  1997年   174篇
  1996年   163篇
  1995年   165篇
  1994年   140篇
  1993年   123篇
  1992年   323篇
  1991年   351篇
  1990年   305篇
  1989年   264篇
  1988年   258篇
  1987年   263篇
  1986年   229篇
  1985年   217篇
  1984年   127篇
  1983年   154篇
  1982年   99篇
  1981年   78篇
  1979年   160篇
  1978年   95篇
  1977年   79篇
  1975年   79篇
  1974年   75篇
  1973年   99篇
  1972年   74篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
45.
Aim: To study the prevalence of filtration-bleb transconjunctival oozing in the first postoperative year after various glaucoma procedures. Methods: Cross-sectional, single-point examination of all filtration blebs in eyes which had glaucoma surgery in the last year. Eyes were examined 3-12 months after surgery and were grouped into non-penetrating (NPGS) and penetrating (PGS)  相似文献   
46.
目的:前瞻性研究青光眼术中应用丝裂霉素C(MMC)对于结膜滤过泡高危因素如无血管化、经结膜的渗漏(TCO)和滤过泡裂孔的影响。方法:一位观察者对进行了青光眼手术联合MMC的125例连续患者的125只眼进行为期2年的前瞻性研究,这些患者最初都成功地建立了滤过通道。巩膜瓣切开前将MMC置于该区,多数患者MMC0.2g/L持续2min。青光眼手术包括小梁切除术、深巩膜切除术和联合手术。将干燥的荧光素试纸置于滤过泡的无血管区,以观察房水外流[点渗漏(PL)或未流出(TCO)]。  相似文献   
47.
Xanthotoxol (XT), 8-hydroxypsoralen, exhibited dose-graded sedative activity in dogs, cats, rats, mice and hamsters. At doses of 5-20 mg/kg intraperitoneally (i.p.) in cats and 3-100 mg/kg orally (p.o.) in dogs, XT blocked predatory mouse/rat killing behavior. In mice, XT (10-300 mg/kg i.p.) exhibited a dose-dependent reduction in locomotor activity but was less potent in this regard than reference diazepam (10-100 mg/kg i.p.). XT in mice (0.1-10.0 mg/kg i.p.) and in hamsters (0.1-10.0 mg/kg p.o.) antagonized amphetamine-induced hypermobility but was less potent than diazepam. XT elevated the electrical threshold in foot-shock-induced fighting behavior in rats. XT (0.1-30.0 mg/kg p.o.) potentiated pentobarbital-induced narcosis in hamsters at otherwise subeffective doses of pentobarbital. Conditioned avoidance responses in rats were not significantly altered with 1-3 mg/kg i.p. and 30-100 mg/kg p.o. doses of XT but 300 mg/kg p.o. blocked both conditioned and unconditioned response. Doses of 100-1000 mg/kg i.p. of XT in mice were used to study 48-h acute toxicity of XT and its LD50 was estimated to be 468 mg/kg. Doses of 10, 40 and 80 mg/kg p.o. were used to study the chronic toxicity of XT in rats for 6 months and no side effects or abnormalities in reproductive activity or endocrine integrity were noted. The F1 generation of rats from 6-month XT-treated parents were free of teratogenic effects.  相似文献   
48.
Because some evidence suggests that cocaine and GBR12935 bind to different sites, we utilized photoaffinity probes from both classes of compounds to see if they label the same protein. [125I]RTI-82 a cocaine analog, and [125I]DEEP, a GBR analog, labeled protein(s) showing the same molecular weight, a similar pharmacological profile and a similar sensitivity to neuraminidase.  相似文献   
49.
Engineering of a variety of rodent tumour cells to secrete either interleukin 2 (IL-2), or interleukin 4 (IL-4), has been demonstrated to reduce their tumorigenicity. However the mechanisms of action of secreted IL-2 and IL-4 have not been compared in a single rodent tumour. Here we demonstrate that the weakly immunogenic murine fibrosarcoma FS29 had reduced growth rate and in some cases was rejected by syngeneic animals, when modified to secrete either IL-2 or IL-4, but not IL-5. Immunohistochemical analysis of tumour nodules undergoing regression showed stimulation of a largely lymphocytic infiltrate by IL-2 and a macrophage and granulocyte infiltrate, with a small number of lymphocytes by IL-4. Indeed, secretion of low levels of IL-2 and IL-4 in combination resulted in optimal rejection, suggesting that the two cytokines might mobilise different and complementary effector cell mechanisms. Both IL-2 and IL-4-secreting cells failed to induce the rejection of admixed, unmodified FS29 cells. The loss of cytokine secreting cells from such admixtures occurred more rapidly for IL-2-secreting cells. Injection of IL-4-secreting, but not IL-2-secreting FS29 cells could protect mice from a delayed challenge with unmodified FS29 cells. These data suggest that IL-4 secretion stimulates the better long-term host anti-tumour response.  相似文献   
50.
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