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   185653篇
  免费   1933篇
  国内免费   739篇
耳鼻咽喉   1214篇
儿科学   6705篇
妇产科学   3098篇
基础医学   17648篇
口腔科学   1721篇
临床医学   13643篇
内科学   32230篇
皮肤病学   922篇
神经病学   16939篇
特种医学   9270篇
外国民族医学   4篇
外科学   29800篇
综合类   4161篇
现状与发展   3篇
一般理论   1篇
预防医学   18775篇
眼科学   3054篇
药学   10555篇
  4篇
中国医学   1162篇
肿瘤学   17416篇
  2024年   35篇
  2023年   192篇
  2022年   424篇
  2021年   557篇
  2020年   397篇
  2019年   361篇
  2018年   22277篇
  2017年   17692篇
  2016年   19816篇
  2015年   1391篇
  2014年   1371篇
  2013年   1323篇
  2012年   7742篇
  2011年   21789篇
  2010年   19307篇
  2009年   11928篇
  2008年   19989篇
  2007年   22240篇
  2006年   1018篇
  2005年   2630篇
  2004年   3835篇
  2003年   4776篇
  2002年   2870篇
  2001年   646篇
  2000年   671篇
  1999年   401篇
  1998年   317篇
  1997年   338篇
  1996年   193篇
  1995年   183篇
  1994年   201篇
  1993年   109篇
  1992年   105篇
  1991年   132篇
  1990年   150篇
  1989年   110篇
  1988年   78篇
  1987年   65篇
  1986年   50篇
  1985年   44篇
  1984年   28篇
  1983年   28篇
  1982年   31篇
  1980年   41篇
  1938年   60篇
  1937年   25篇
  1935年   22篇
  1934年   30篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.  相似文献   
62.
Pituitary metastases of solid tumours are infrequent, specially as a first manifestation. When they happen, they are usually due to breast or lung cancer and are asymptomatic or produce diabetes insipidus. It is very strange that they produce hormonal deficiency. We present a case report of a bronchogenic adenocarcinoma in a 65-year-old man which began with panhypopituitarism, diabetes insipidus and visual alterations. Magnetic resonance imaging revealed a large sellar mass, with clivus infiltration and invading the right cavernous sinus. The biopsy result was adenocarcinoma metastases from lung cancer.  相似文献   
63.
Background. Accepted practices of informed consent often result in suboptimal patient understanding of research studies.Methods. This pilot study aimed to assess trial-specific tailored materials, compared to a widely used generic booklet about clinical trials, randomly assigned to 118 candidates for cancer clinical trials. Study outcomes were: satisfaction with decision-making; satisfaction with materials; and subjective understanding of the clinical trial.Results. There were no major differences between groups. Participants rated tailored materials higher as a useful reference.Conclusions. Trial-specific materials hold utility for reference during clinical trials. Studies of informed consent are feasible, although important factors limit research.  相似文献   
64.
The leaf essential oil of Eugenia zuchowskiae from Monteverde, Costa Rica, has been obtained by hydrodistillation and analyzed by GC–MS. The principal constituents of E. zuchowskiae leaf oil were α-pinene (28.3%), β-caryophyllene (13.2%), α-humulene (13.1%), and α-copaene (8.1%). The leaf essential oil of E. zuchowskiae showed pronounced in-vitro cytotoxic activity against MCF-7, MDA-MB-468, and UACC-257 human tumor cell lines. The major components showed cytotoxic activities comparable to doxorubicin (LC50 14–70 μg/ml).  相似文献   
65.
采用SD大鼠一侧大脑中动脉阻断致局限性脑缺血模型。脑缺血后迅速断头置于液氮中,HPLC外标定量法测定各磷脂组分。观察脑缺血1、5、15、60、360min时脑细胞膜磷脂含量变化。结果显示,PI在缺血早期显著低于对照组(P<0.01~0.05);PE、PC早期仅呈下降趋势,PE在缺血60min组、PC缺血360min组显著低于对照组(P<0.01~0.05)。PS在缺血全过程中变化轻微(P>0.05)。提示磷脂降解与脑缺血存在一定关系,缺血早期首先出现脑细胞膜功能磷脂降解,膜结构磷脂则在缺血后期出现显著变化,且PE较PC优先降解。  相似文献   
66.
67.
68.
The prevalence of primary headache (PH) in a multiple sclerosis (MS) sample vs. control healthy subjects was investigated at a neurological clinic in 2004–2005: 122 of 238 (51%) MS patients and 57 of 238 (23%) controls proved to be affected by headache. The groups did not differ for the rates of PH types. Headache types of MS patients were comparable to those of PH patients that were observed at the same institute in a case-control comparison. First symptoms of headache preceded those of MS in two thirds of cases. Headache features did not significantly change after MS onset. Comorbidity of MS and PH could be explained by some common clinical and biological traits.  相似文献   
69.
Single-agent chemotherapy of metastatic breast cancer is the treatment of choice in patients with slow tumor progression and asymptomatic disease. In this patient group, the choice of drugs is based more on good tolerability than on efficacy. By contrast, symptomatic or rapidly progressing disease requires the use of highly active regimens where more weight is put on reliable antitumor activity. While anthraycline-based combination regimens have set the standard of effective treatment, the addition of docetaxel (and to a lesser extent paclitaxel) has improved tumor response, but failed to induce a consistent prolongation of survival. Based on retrospective analyses, it is hypothesised that the combined use of anthracyclines and taxanes in first-line therapy may be most beneficial in defined subgroups: after adjuvant chemotherapy, in patients with HER-2 gene amplification, possibly also in patients with rapidly progressing visceral disease.  相似文献   
70.
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