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   8204篇
  免费   462篇
  国内免费   15篇
耳鼻咽喉   113篇
儿科学   309篇
妇产科学   345篇
基础医学   1099篇
口腔科学   151篇
临床医学   598篇
内科学   2025篇
皮肤病学   151篇
神经病学   712篇
特种医学   194篇
外科学   1249篇
综合类   19篇
预防医学   570篇
眼科学   159篇
药学   509篇
中国医学   34篇
肿瘤学   444篇
  2023年   20篇
  2022年   45篇
  2021年   121篇
  2020年   77篇
  2019年   136篇
  2018年   144篇
  2017年   94篇
  2016年   101篇
  2015年   161篇
  2014年   209篇
  2013年   271篇
  2012年   377篇
  2011年   403篇
  2010年   221篇
  2009年   194篇
  2008年   438篇
  2007年   495篇
  2006年   506篇
  2005年   490篇
  2004年   476篇
  2003年   419篇
  2002年   437篇
  2001年   335篇
  2000年   365篇
  1999年   283篇
  1998年   89篇
  1997年   75篇
  1996年   82篇
  1995年   70篇
  1994年   58篇
  1993年   61篇
  1992年   174篇
  1991年   154篇
  1990年   123篇
  1989年   97篇
  1988年   103篇
  1987年   106篇
  1986年   71篇
  1985年   68篇
  1984年   48篇
  1983年   39篇
  1982年   26篇
  1981年   29篇
  1979年   30篇
  1973年   24篇
  1971年   20篇
  1970年   31篇
  1969年   21篇
  1968年   35篇
  1967年   21篇
排序方式: 共有8681条查询结果,搜索用时 156 毫秒
1.
2.
3.
OBJECTIVE: To assess antipsychotic medication in the treatment of schizophrenia, based on trial drop-out rates. METHOD: The studies included were randomised controlled trials that compared any of the four clinically best-established atypical antipsychotics (quetiapine, olanzapine, risperidone or clozapine) against either of two typical antipsychotics regarded as the gold standard (haloperidol or chlorpromazine). RESULTS: Meta-analysis indicated less risk of all-cause patient withdrawal from atypical medication trials where dosage was flexible, in both the short, relative risk (RR) 0.70 (95% CI 0.64-0.76), P<0.00001, and long term, RR 0.72 (0.65-0.80), P<0.00001. Similar results were observed for withdrawal due to adverse events, RR: 0.54 (0.41-0.72), P<0.0001. Nevertheless, the favourable effects of atypical medication disappeared in trials relying on fixed dosage. CONCLUSIONS: We detected a significant positive effect in terms of the outcome of treatment discontinuation for atypical versus typical medication, though only where the use of flexible rather than fixed doses (closer to an experimental control situation) was possible.  相似文献   
4.
Computed tomography of the brain in the Smith-Lemli-Opitz syndrome   总被引:1,自引:0,他引:1  
Computed tomographic (CT) scans of the brain in a child with Smith-Lemli-Opitz syndrome revealed enlargement of the ventricular system, hypoplasia of the cerebellum, and abnormal thickening of the gray matter, consistent with pachygyria. These findings have been previously noted in autopsies performed on patients with this disorder. We conclude that CT scanning is a valuable tool in the evaluation of children suspected of having the Smith-Lemli-Opitz syndrome.  相似文献   
5.
The nerve action potential at the elbow and somatosensory evoked potentials (SEPs) at the scalp were recorded over 30 minutes of tourniquet-induced limb ischaemia in 10 diabetic patients and 10 controls. According to the SEP changes, an increased resistance to nerve ischaemia in diabetic patients was observed. The pathways involved in SEP conduction are discussed.  相似文献   
6.
7.
8.
Men who had high, medium and low blood pressure at age 18 (compulsory screening for military service in Stockholm) were examined ten years later at age 28. Interviewers, having had no information regarding past or present blood pressure, interviewed them about life events experienced during the year preceding the examination. Men with high blood pressure at rest reported fewer life events for the past year than other men. Furthermore, high plasma adrenaline levels at rest were associated with few reported life events.  相似文献   
9.
We present a modified EEG montage that detects small interchannel time differences and assists in localizing the epileptogenic focus. Regions with apparently synchronous epileptic discharges are displayed simultaneously in referential and subtraction derivations. The subtraction derivation is a bipolar configuration of two regions of interest that are not necessarily adjacent. The referential derivation reveals the polarity, voltage, and morphology of the two discharges, and the subtraction derivation detects asynchrony; the combined reference-subtraction derivation thus indicates the region that is activated first.  相似文献   
10.
Purpose: Increasingly, evidence has shown that human papillomavirus (HPV) plays a role in the induction of certain carcinomas. The presence of HPV sequences in 56 previously untreated oral and pharyngolaryngeal carcinomas was examined by the polymerase chain reaction (PCR).Materials and Methods: After DNA extraction, samples underwent 40 replication cycles with specific oligonucleotide primers corresponding to sequences from the E6 open-reading frame of HPV-6b, HPV-16, and HPV-18. To determine the E6 genomic integration, positive samples were processed with specific primers for the corresponding HPV L1 genes. Genomic HPV DNA cloned into PBR 322 was used as positive control.Results: HPV E6 DNA of the 6b and 16 types was detected in 14 patients (25%). The L1 gene was not present.Conclusion: Detected HPV E6 DNA might be integrated into the cell genome in the positive cases as indicated by the absence of the L1 gene-coding for the viral capside. Histological and clinical parameters, such as tumor location, degree of differentiation, stage, recurrence, and survival rates, were unrelated to the presence of HPV.  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