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   19662篇
  免费   1552篇
  国内免费   44篇
耳鼻咽喉   194篇
儿科学   506篇
妇产科学   340篇
基础医学   2584篇
口腔科学   684篇
临床医学   1913篇
内科学   4579篇
皮肤病学   191篇
神经病学   1841篇
特种医学   786篇
外国民族医学   1篇
外科学   2454篇
综合类   402篇
一般理论   17篇
预防医学   1708篇
眼科学   527篇
药学   1418篇
中国医学   11篇
肿瘤学   1102篇
  2022年   102篇
  2021年   268篇
  2020年   150篇
  2019年   259篇
  2018年   302篇
  2017年   251篇
  2016年   268篇
  2015年   328篇
  2014年   475篇
  2013年   819篇
  2012年   1079篇
  2011年   1154篇
  2010年   611篇
  2009年   622篇
  2008年   1153篇
  2007年   1255篇
  2006年   1275篇
  2005年   1255篇
  2004年   1177篇
  2003年   1135篇
  2002年   1142篇
  2001年   300篇
  2000年   289篇
  1999年   293篇
  1998年   292篇
  1997年   255篇
  1996年   224篇
  1995年   232篇
  1994年   197篇
  1993年   181篇
  1992年   223篇
  1991年   200篇
  1990年   228篇
  1989年   189篇
  1988年   217篇
  1987年   208篇
  1986年   197篇
  1985年   195篇
  1984年   180篇
  1983年   160篇
  1982年   211篇
  1981年   208篇
  1980年   160篇
  1979年   143篇
  1978年   109篇
  1977年   90篇
  1975年   81篇
  1974年   101篇
  1973年   80篇
  1972年   80篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
101.
Data are limited on seizure recurrence after antiepileptic drug (AED) discontinuation in operated seizure-free patients. We reviewed seizure outcome in patients who came off AEDs after being seizure-free for 2 years following temporal lobe surgery in our center. Thirty-nine (68%) of 57 patients who discontinued AED therapy remained seizure-free. They had a younger age at surgery than the group with seizure recurrence (p=0.01). Earlier surgery may be a favorable predictor for seizure freedom after AED discontinuation.  相似文献   
102.
103.
Background: The Farnsworth D15 test is designed to categorise colour vision deficiency as severe or moderate. The level of difficulty of the test was set so that those who passed it should be able to recognise surface colour codes, such as those used for electrical wiring. The test is widely used to provide advice to patients with abnormal colour vision and is often used for occupational selection when reliable recognition of surface colour codes is required. However, there has been only one previous study of the correlation between performance at the D15 test and the naming of surface colour codes and there has been no study of whether a person who passes the D15 can reliably name surface colours. Methods: One hundred and two people aged 11 to 65 years with abnormal colour vision were recruited from consecutively presenting optometric patients and were asked to name the colours of fabric, paint and cotton thread samples. There were 10 colours in each class of material and the samples were presented in a large (five to 10 degree angular subtense) and small size (2.5 deg and a single thread). The errors made were compared to those made by an age‐matched control group of equal size with normal colour vision. Results: The correlations between the Farnsworth D15 colour confusion index and colour naming errors were 0.62 for the large stimuli and 0.73 for the small stimuli. Its sensitivity and specificity identifymg those who made more errors than the worst performing colour normal person were 0.80 and 0.69 (large stimuli) and 0.75 and 0.71 (small stimuli). A Nagel anomaloscope range of less than 35 scale units provides essentially the same sensitivity and specificity. Conclusions: About 40 per cent of those with abnormal colour vision can name the main colours correctly under good visibility conditions. The D15 test is an imperfect predictor of those who can name surface colour codes correctly but it does provide useful information for general counselling. It is not suitable as a single test for occupational selection because it will pass 20 per cent who cannot name surface colours correctly and fail 30 per cent who can. In occupations in which recognition of surface colour codes is of critical importance, it may be best not to select people with abnormal colour vision because of the lack of a colour vision test that is a perfect predictor of the ability to recognise surface colours.  相似文献   
104.
105.
106.
107.
108.
109.
Ethanol is a recognized immunosuppressive agent in the chronic alcoholic. However, the effects of ethanol exposure on the developing immune system have not been extensively investigated. This study evaluated the effects of early postnatal ethanol exposure, via breast milk, on splenic lymphocyte differentiation antigen expression in offspring reared by ethanol-fed mice. Maternal mice were fed a liquid diet containing 20% ethanol-derived calories during pregnancy (E-P), pregnancy and lactation (E-PL), or lactation (E-L). Ad libitumfed (C) and pair-fed (PF) control groups, fed a control liquid diet, were included. Expression of differentiation antigens on splenic lymphocytes from 21-day-old offspring reared by females in 1 of the 3 ethanol exposure conditions was evaluated by flow cytometry. Offspring reared by E-P females had similar numbers of splenic lymphocytes as offspring reared by C and pair-fed during pregnancy (PF-P) females. In contrast, offspring reared by E-PL and E-L females had fewer splenic lymphocytes than both PF-PL and PF-L (respectively), and C offspring. The number of Thy 1.2+, CD4+, CD8+, and IgG+ (B-cell) splenic lymphocytes was reduced in E-PL and E-L offspring compared with PF and C offspring. E-P offspring had fewer CD4+ and IgG+ splenic lymphocytes than C, but not PF-P, offspring. The percentage of Thy 1.2+ splenic lymphocytes was significantly reduced among E-PL and E-L offspring compared with PF-PL and PF-L (respectively), and C offspring. These results suggest that ethanol exposure of female mice during pregnancy, pregnancy and lactation, or lactation alone, alters the phenotypic development of splenic lymphocytes of offspring reared by these females. The greatest effect on differentiation antigen expression occurred when females consumed ethanol during the period of lactation. We speculate that direct exposure of the nursing offspring to ethanol via the breast milk was responsible for the reductions in specific splenic lymphocyte populations. These data demonstrate that mice reared by females fed ethanol during the early postnatal period have a marked depletion of each of the major subpopulations of splenic lymphocytes, and that Thy 1.2+ lymphocytes are differentially sensitive to ethanol.  相似文献   
110.
Aims. Examine the relationship between buprenorphine and norbuprenorphine plasma concentrations with subject-reported withdrawalsymptomatology during buprenorphine dose induction, maintenance treatment (daily and alternate-day dosing) and withdrawal . Design. Two groups of randomly assigned subjects inducted onto buprenorphine and maintained on 8 mg daily by the sublingual route for 18 days. Group 1 continued to receive daily buprenorphine to day 36. Group 2 subjects received alternate-day dosing of buprenorphine and placebo on days 19 to 36. Both groups received placebo on days 37 to 52 . Setting. Inpatient facilities at the Addiction Research Center, Intramural Research Center, NIDA, Baltimore, MD . Participants. Eleven male, heroin-dependent volunteers participating in a research study . Intervention. Medications for treatment of withdrawal symptoms were prescribed as needed after day 39 (72 hours after the last dose of buprenorphine) . Measurements. Plasma concentrations of buprenorphine and norbuprenorphine, withdrawal symptomatology and pupil diameter . Findings. The mean steady-state buprenorphine plasma concentration (24 hours) after daily administration of sublingual buprenorphine for study days 21-35 was 0.80 ng/ml, and the mean alternate day steady-state buprenorphine plasma concentration (24 hours) was 0.77 ng/ml. Daily and alternate day steady-state norbuprenorphine plasma concentrations were 1.10 and 0.90 ng/ml, respectively. Predicted alternate day steady-state buprenorphine and norbuprenorphine plasma concentrations at 48 hours were 0.49 ng/ml and 0.57 ng/ml, respectively. Withdrawal scores varied inversely with plasma concentration. There were no significant differences between Groups 1 and 2 during steady-state (days 21-35) with regard to withdrawal scale scores or pupillary diameter. The overall, mean terminal elimination half-lives for buprenorphine and norbuprenorphine were 42 and 57 hours, respectively . Conclusions. During daily buprenorphine maintenance, plasma concentrations greater than 0.7 ng/ml of buprenorphine and norbuprenorphine were associated with minimal withdrawal symptoms. The long elimination half-life of buprenorphine suggested that increasing the buprenorphine dose with alternate-day administration may provide an effective, flexible therapy regimen for the treatment of opioid dependence.  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