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   63712篇
  免费   4658篇
  国内免费   148篇
耳鼻咽喉   827篇
儿科学   1738篇
妇产科学   1598篇
基础医学   10495篇
口腔科学   1683篇
临床医学   6021篇
内科学   12804篇
皮肤病学   969篇
神经病学   5986篇
特种医学   2652篇
外国民族医学   45篇
外科学   8229篇
综合类   533篇
一般理论   83篇
预防医学   4985篇
眼科学   1219篇
药学   4611篇
中国医学   162篇
肿瘤学   3878篇
  2022年   469篇
  2021年   1033篇
  2020年   655篇
  2019年   928篇
  2018年   1128篇
  2017年   787篇
  2016年   922篇
  2015年   1096篇
  2014年   1348篇
  2013年   2331篇
  2012年   3019篇
  2011年   3102篇
  2010年   2237篇
  2009年   1875篇
  2008年   2812篇
  2007年   2951篇
  2006年   2935篇
  2005年   2785篇
  2004年   2834篇
  2003年   2582篇
  2002年   2646篇
  2001年   2157篇
  2000年   2208篇
  1999年   1982篇
  1998年   875篇
  1997年   730篇
  1996年   644篇
  1995年   667篇
  1994年   554篇
  1993年   604篇
  1992年   1447篇
  1991年   1392篇
  1990年   1335篇
  1989年   1319篇
  1988年   1100篇
  1987年   1102篇
  1986年   1045篇
  1985年   959篇
  1984年   692篇
  1983年   648篇
  1982年   458篇
  1981年   440篇
  1980年   378篇
  1979年   624篇
  1978年   374篇
  1977年   357篇
  1975年   373篇
  1974年   414篇
  1973年   347篇
  1972年   340篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
23.
24.
Abstract: Data from the National Education Longitudinal Study were combined with census data at the zip code level to examine the impact of neighborhood racial and ethnic diversity and consolidated inequality, in addition to individual, family, and school factors, on the likelihood of dropping out of high school. Results indicate that while the effects for diversity and consolidated inequality did not support the stated hypotheses, main effects for family risk and prior academic achievement were significant and in the stated direction. Also, when controlling for individual, family, school, and neighborhood characteristics, African Americans were less likely than White students to drop out of school. Implications for contextual effects research and educational outcomes are discussed.  相似文献   
25.
26.
French asthma patients may be supervised by general practitioners (GPs) and/or specialists. Therefore, this study examined asthma management in patients exclusively supervised by specialists (SPE), GPs, (GP) and both (GP+SPE group), and compared the findings. Asthma patients were consecutively recruited in 348 pharmacies. Each patient completed a questionnaire providing data on personal characteristics, asthma management, perception of disease and asthma supervision. Asthma control was measured using the Asthma Control Test. Questionnaires were linked to computerised records of medications which had been dispensed before inclusion in the study. From the 1,256 patients (mean age = 36.1 yrs, 54.3% females), 11.4, 36.6, and 52.0% were placed in the SPE, GP, and GP+SPE groups, respectively. During the previous 4 weeks, most patients in the SPE group were properly controlled (52.2 versus 26.4 and 21.5% in GP and GP+SPE groups, respectively). The SPE group made more use of fixed combinations of long-acting beta agonist and inhaled corticosteroid, while receiving less short-acting beta agonists, antitussives and antibiotics. Striking differences in symptoms and asthma management were observed according to the type of asthma supervision. The current results strongly support the need to improve the management of asthma in primary care, and the coordination of care between general practitioners and specialists.  相似文献   
27.
28.
In six patients suffering from severe early dumping and six patients with late dumping after peptic ulcer surgery, the effect of the somatostatin analogue SMS 201-995 was compared with placebo. In early dumpers subcutaneous administration of 50 micrograms SMS 201-995 prior to meal ingestion induced a strong improvement of dumping symptoms as reflected by a decrease of the Sigstad dumping score from 12 +/- 2 during placebo to 5 +/- 2 (p less than 0.05). Furthermore, the postprandial increase of pulse rate was abolished; maximum pulse rate decreased from 85 +/- 7 beats/min to 67 +/- 7 beats/min (p less than 0.05). SMS 201-995 did not significantly affect postprandial changes in packed cell volume. In late dumpers 50 micrograms SMS 201-995 reduced peak plasma insulin after oral glucose from 173 +/- 16 mU/L during placebo to 35 +/- 9 mU/L during SMS 201-995 (p less than 0.05) and increased individual plasma glucose nadirs from 1.9 +/- 0.3 mmol/L to 7.5 +/- 3.3 mmol/L (p less than 0.01). Both in early and late dumpers SMS 201-995 improved postprandial expiratory breath hydrogen excretion indicating slowing of gastrointestinal hurry. SMS 201-995 is a powerful therapeutic agent for the management of patients suffering from the dumping syndrome after gastric surgery.  相似文献   
29.
30.
Background: The association between aluminium and dialysis encephalopathy and deterioration of the neurological state during desferrioxamine treatment of dialysis patients is well established. At present little is known about the speciation and the mechanisms underlying the element's neurotoxicity. Methods. Aluminium speciation was performed in cerebrospinal fluid samples of acutely aluminium-intoxicated dialysis patients using a recently developed high-performance liquid chromatographic/electro-thermal atomic absorption spectrometric hybrid method. Results: Baseline cerebrospinal fluid aluminium levels of samples taken shortly after the intoxication were low but elevated (5.0±2.0 &mgr;g/l, n=3) as compared to subjects with normal renal function (<1 &mgr;g/l). In contrast to the situation noted in serum and to the iron speciation in cerebrospinal fluid, aluminium was not bound to transferrin but appeared as two distinct compounds, the main fraction eluting at the elution volume of aluminium citrate/silicate. The second compound was not identified. Forty-four hours after desferrioxamine administration the cerebrospinal fluid aluminium levels had increased up to a concentration of 10.3±2.5 &mgr;g/l (n=3). This was accompanied by a change in the speciation profile with aluminium appearing at the elution volume of aluminoxamine. Conclusion: Our findings may contribute to a better understanding of the neurotoxic effects of aluminium and its desferrioxamine chelate in dialysis patients.  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