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   175367篇
  免费   1005篇
  国内免费   2篇
耳鼻咽喉   1121篇
儿科学   6686篇
妇产科学   3005篇
基础医学   16591篇
口腔科学   1528篇
临床医学   12351篇
内科学   30806篇
皮肤病学   657篇
神经病学   16408篇
特种医学   8984篇
外科学   28747篇
综合类   2307篇
预防医学   18041篇
眼科学   2792篇
药学   9396篇
中国医学   624篇
肿瘤学   16330篇
  2021年   23篇
  2019年   33篇
  2018年   21935篇
  2017年   17370篇
  2016年   19517篇
  2015年   909篇
  2014年   808篇
  2013年   777篇
  2012年   6936篇
  2011年   21000篇
  2010年   18808篇
  2009年   11502篇
  2008年   19457篇
  2007年   21663篇
  2006年   528篇
  2005年   2148篇
  2004年   3377篇
  2003年   4331篇
  2002年   2462篇
  2001年   282篇
  2000年   431篇
  1999年   171篇
  1998年   204篇
  1997年   206篇
  1996年   90篇
  1995年   105篇
  1994年   105篇
  1993年   60篇
  1992年   49篇
  1991年   95篇
  1990年   139篇
  1989年   76篇
  1988年   54篇
  1987年   43篇
  1986年   25篇
  1985年   32篇
  1984年   21篇
  1983年   21篇
  1982年   27篇
  1980年   45篇
  1974年   23篇
  1970年   22篇
  1969年   21篇
  1939年   20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 15 毫秒
141.
142.

Objective  

To investigate an initial approach of radiotherapy, which produces cellular radiation injury by high dose in one fraction.  相似文献   
143.

Background  

Nasal NK/T cell lymphoma is an aggressive disease and has a poor prognosis. Nasal NK/T cell lymphoma is refractory to conventional chemotherapy and has strong tendency of widespread relapse or dissemination into distant sites.  相似文献   
144.

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   
145.
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   
146.
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   
147.
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   
148.
Objective: To evaluate the effect and safety of clinical use of zoledronic acid in the treatment of malignant hypercalcemia. Methods: A multi-center, open phase II clinical trial was conducted in 15 cases with malignant hypercalcemia who received zoledronic acid intravenously for 15 min. The level of blood calcium and side effects were recorded regularly within 28 days after injection. Results: One case was dropped out due to bad compliance. The complete response rate (the corrected serum calcium was reduced to normal level) was 100.00% (14/14). The medium time of complete response rate was 5.07 days. The medium maintain time was 22.30 days. Slight, or moderate fever was observed. Conclusion: Zoledronic acid can effectively reduce the malignant hypercalcemia. The use of zoledronic acid appears to be safety and convenient.  相似文献   
149.
The relationship between the bioenergetic status of human glioma xenografts in nude mice and morphometric parameters of the perfused vascular architecture was studied using (31)P magnetic resonance spectroscopy (MRS), fluorescence microscopy and two-dimensional digital image analysis. Two tumour lines with a different vascular architecture were used for this study. Intervascular distances and non-perfused area fractions varied greatly between tumours of the same line and tumours of different lines. The inorganic phosphate-nucleoside triphosphate (P(i)/NTP) ratio increased rapidly as mean intervascular distances increased from 100 microm to 300 microm. Two morphometric parameters - the percentage of intervascular distances larger than 200 microm (ivd200) and the non-perfused area fraction at a distance larger than 100 microm from a nearest perfused vessel (area100), - were deduced from these experiments and related to the P(i)/NTP ratio of the whole tumour. It is assumed that an aerobic to anaerobic transition influences the bioenergetic status, i.e. the P(i)/NTP ratio increased linearly with the percentage of ivd200 and the area100.  相似文献   
150.
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