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   125917篇
  免费   9124篇
  国内免费   212篇
耳鼻咽喉   1135篇
儿科学   3509篇
妇产科学   2597篇
基础医学   19656篇
口腔科学   3303篇
临床医学   10656篇
内科学   25557篇
皮肤病学   2180篇
神经病学   12132篇
特种医学   5205篇
外国民族医学   9篇
外科学   15755篇
综合类   533篇
现状与发展   1篇
一般理论   106篇
预防医学   14399篇
眼科学   1964篇
药学   7378篇
中国医学   236篇
肿瘤学   8942篇
  2023年   540篇
  2022年   898篇
  2021年   1947篇
  2020年   1416篇
  2019年   2060篇
  2018年   2588篇
  2017年   2204篇
  2016年   2390篇
  2015年   2677篇
  2014年   3671篇
  2013年   4793篇
  2012年   7372篇
  2011年   7443篇
  2010年   3868篇
  2009年   4050篇
  2008年   6591篇
  2007年   6800篇
  2006年   6547篇
  2005年   6198篇
  2004年   5286篇
  2003年   4993篇
  2002年   4546篇
  2001年   4441篇
  2000年   4386篇
  1999年   3915篇
  1998年   1612篇
  1997年   1337篇
  1996年   1407篇
  1995年   1154篇
  1994年   1078篇
  1993年   994篇
  1992年   2680篇
  1991年   2406篇
  1990年   2289篇
  1989年   2138篇
  1988年   1962篇
  1987年   1712篇
  1986年   1630篇
  1985年   1560篇
  1984年   1111篇
  1983年   967篇
  1982年   524篇
  1981年   467篇
  1980年   395篇
  1979年   859篇
  1978年   525篇
  1977年   431篇
  1974年   417篇
  1973年   409篇
  1972年   366篇
排序方式: 共有10000条查询结果,搜索用时 32 毫秒
91.
An elderly female alcohol and benzodiazepine addict presented with an atypical amnestic episode. Five days later she showed several complex partial seizures as main signs of a withdrawal state. The value of the EEG in the differential diagnosis of amnestic syndromes is emphasized. Temporolimbic involvement in withdrawal states is discussed and our ignorance regarding drug dependence and withdrawal in the elderly is stressed. It is suggested that late-onset partial seizures with unknown etiology in the elderly might be more often related to drug dependence than generally accepted.  相似文献   
92.
In six patients with essential hypertension, the pharmacokinetics of nisoldipine were investigated before, during, and after 4 weeks of treatment. On day 1, nisoldipine was infused intravenously (i.v. 2 mg in 2 h); on day 2, oral nisoldipine treatment (10-mg tablets twice daily) was started for 4 weeks. During this period, patients came to the hospital six times, on which occasions blood samples were taken for the determination of trough and peak concentrations of nisoldipine. After 4-week treatment, the infusion experiment was repeated. In the first infusion experiment, systemic clearance was 1.02 +/- 0.23 L/min (mean +/- SD), terminal half-life (t1/2) was 15.4 +/- 6.7 h, and volume of distribution was 5.9 +/- 1.8 L/kg. After 4 weeks, these parameters had not changed significantly. Nisoldipine lowered blood pressure (BP) in all patients, whereas forearm blood flow and heart rate (HR) increased. Neither were the hemodynamic changes different after the oral treatment period, although basal BP was lower than before oral treatment. No accumulation of nisoldipine occurred during the 4-weeks treatment period.  相似文献   
93.
94.
95.
The study was designed to identify diet and carcinogen-dependent ultrastructural changes in the epithelium of macroscopically normal colonic mucosa in primates. Seventy adult female vervet monkeys were divided into seven equal treatment groups. Four received a Western high-fat low fibre diet (WD), two a prudent low-fat higher fibre diet (PD) and one a control low-fat high fibre diet (CD). Three groups (2 WD, 1 PD) received dimethylhydrazine intramuscularly at 14 day intervals. After 18 months, monkeys of two groups on the WD were transferred to the PD (WD----PD) and 30 months later all were killed. Mucosae of caecum, colon transversum and rectum were examined by scanning and transmission electron microscopy and showed close similarity to that of humans. Rectal mucosae showed increased surface goblet cell secretory activity, mucin production and microvillar changes related to WD and WD----PD. The enhancing effect of a carcinogen on ultrastructural changes such as cellular pleomorphism, cytoplasmic interbridging, nuclear and nucleolar irregularities and appearance of argentaffin cells in the free surface epithelium were noted predominantly in high-fat treated animals. Such changes observed in the upper part of crypt, orifice and free surface epithelium can be characteristic for precancerous change and could be utilised practically in the detection of precursor lesions of the colon.  相似文献   
96.
97.
The Dutch orthotopic liver transplant programme was evaluated recently. This article focuses on the physical functioning, the pattern of activities, the social functioning and the level of wellbeing of 31 transplant patients. Data were generated by means of questionnaires and interviews. The majority of the patients look upon themselves as 'healthy'. Their physical potential has greatly improved. Three-quarters of the patient group think they are able to go back to work. However, from the interviews it appears that one third of the patient group suffered from more or less serious psychological problems following transplantation.  相似文献   
98.
Inhibition of protein synthesis can alter cellular responsiveness to the classical anticancer drugs. The in vitro response of Chinese hamster ovary (CHO) cells to cisplatin with or without sparsomycin (Sm) was studied with the use of [3H]leucine and [methyl-3H]thymidine incorporation and clonogenic assay. Pretreatment of exponentially growing CHO cells with 1 microgram Sm/ml for 3 or 5 hours decreased [3H]leucine incorporation by 20% and resulted in significant resistance to cisplatin (P = .005). Sm in a concentration of 10 micrograms/ml reduced [3H]leucine and [methyl-3H]thymidine incorporation after 3 hours by 92 and 84%, respectively, and resulted in potentiation of the cisplatin cytotoxicity (P = .004). This effect was the same in the case of nonproliferating cells (P = .005), while protection due to Sm (1 microgram/ml) was seen only during cell proliferation. Simultaneous incubation and postincubation with Sm proved to have much less or no potentiating effect on cisplatin. The mechanisms of both protection and potentiation are still not clear, but our data indicate that Sm is a promising drug for further studies on the modulation of the cancer cell response to classical anticancer drugs.  相似文献   
99.
Exposure of ZR-75-1 human breast cancer cells for 48 h to human recombinant interferon alpha (IFN alpha) resulted in increased expression of oestrogen receptors as measured in a whole cell binding assay. This effect was inversely proportional to dose being significant following treatment with 10-100 IU IFN ml-1 and was only observed at a low initial cell plating density. The extent of the increase in oestrogen receptor levels ranged from 1.2- to 7.2-fold following treatment with 10 IU IFN ml-1. No increase in progesterone receptor expression was observed under the same experimental conditions. Concentrations of IFN which increased oestrogen receptor levels had no effect on cell proliferation. IFN (500 IU ml-1) inhibited cell proliferation and the combination of this treatment with tamoxifen (2 microM) had a greater anti-proliferative effect than either drug alone although there was no evidence of synergism. However, a 5-day pretreatment of cells with IFN (10 IU ml-1) markedly sensitised them to the growth-inhibiting effect of a subsequent 6-day exposure to tamoxifen.  相似文献   
100.
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