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   7513篇
  免费   301篇
  国内免费   25篇
耳鼻咽喉   55篇
儿科学   86篇
妇产科学   93篇
基础医学   873篇
口腔科学   194篇
临床医学   495篇
内科学   1693篇
皮肤病学   171篇
神经病学   514篇
特种医学   282篇
外科学   1289篇
综合类   29篇
预防医学   230篇
眼科学   47篇
药学   996篇
中国医学   16篇
肿瘤学   776篇
  2023年   10篇
  2022年   33篇
  2021年   53篇
  2020年   30篇
  2019年   40篇
  2018年   71篇
  2017年   57篇
  2016年   70篇
  2015年   68篇
  2014年   110篇
  2013年   142篇
  2012年   257篇
  2011年   329篇
  2010年   167篇
  2009年   163篇
  2008年   313篇
  2007年   378篇
  2006年   368篇
  2005年   403篇
  2004年   340篇
  2003年   366篇
  2002年   383篇
  2001年   360篇
  2000年   383篇
  1999年   327篇
  1998年   100篇
  1997年   85篇
  1996年   83篇
  1995年   67篇
  1994年   69篇
  1993年   61篇
  1992年   239篇
  1991年   231篇
  1990年   234篇
  1989年   211篇
  1988年   210篇
  1987年   186篇
  1986年   174篇
  1985年   179篇
  1984年   98篇
  1983年   83篇
  1982年   43篇
  1981年   29篇
  1980年   26篇
  1979年   69篇
  1978年   35篇
  1977年   18篇
  1976年   12篇
  1975年   11篇
  1969年   10篇
排序方式: 共有7839条查询结果,搜索用时 46 毫秒
11.
12.
13.
Ultraviolet radiation of 8-methoxypsoralen (8-MOP) in the presence of various polyamines resulted in stable photoproducts that were very soluble in water and showed hyaluronidase-activating properties. Among them, the photoproducts obtained from the reaction systems of 8-MOP-spermine and 8-MOP-spermidine markedly activated hyaluronidase. The enzyme activity was not affected by 8-MOP alone and the photoproduct of 8-MOP (8-MOP-P). From these facts, it was suggested that the photoproducts with hyaluronidase-activating properties might play an important role in the onset of 8-MOP-induced photosensitivity.  相似文献   
14.
We measured the plasma free 3-methoxy-4-hydroxyphenylglycol (MHPG) levels and the serum cortisol levels before and after the oral administration of dexamethasone. There was not a significant difference in the plasma free MHPG levels between the patients with major depression and normal subjects. There was a significant positive correlation between the plasma MHPG levels and postdexamethasone cortisol levels in patients with major depression. This indicates that there exists a certain relation between abnormalities of the central noradrenergic systems and hypothalamic-pituitary-adrenal axis in patients with major depression. The mean total scores of the Hamilton Rating Scale for Depression of the first (MHPG less than 5 ng/ml) and third (10 ng/ml less than or equal to MHPG) groups were significantly higher than those of the second (5 less than or equal to MHPG less than 10 ng/ml) group.  相似文献   
15.
We previously reported that the Guardian Bio-Threat Alert (BTA) system could detect (detection limit: about 0.1 μg/ml) staphylococcal enterotoxin B (SEB), botulinum toxins (BTX) A and B, and ricin, with no interference by white-powdered materials or colored matrices. In this study, the capability of the BTA system was further assessed. With 10 min of preheating at 60°C, all toxins could be detected, but with preheating at 80°C, BTX A and B and ricin became undetectable. About 20% SEB could be detected after heating at 80°C, but this detection ability was completely removed after heating at 100°C. The effects of chemicals usually used for decontamination, such as sodium hypochlorite, hydrogen peroxide, formaldehyde, and sodium nitrite, on the detectability of SEB, BTX A, or ricin in the BTA system were also tested. The concentrations giving 50% line intensity for SEB, BTX A, and ricin were 3.1, 11, and 15 μM for sodium hypochlorite and 88, 210, and 60 mM for formaldehyde, respectively. The addition of hydrogen peroxide or sodium nitrite did not decrease the detectability even when used at high concentrations.  相似文献   
16.
Antibiotics 6108 A1, B, C and D, a new series of analogues of rosaramicin, were found together with rosaramicin, juvenimicin A4 and M-4365 A1 from the cultured broth of strain BA06108 which was assigned to be a new species of Micromonospora. 6108 A1 and C showed inhibitory activity against Gram-positive and some Gram-negative bacteria as potent as rosaramicin and exhibited low acute toxicity in mice. However, 6108 B showed less potent antimicrobial activity and 6108 D showed higher toxicity than those two antibiotics.  相似文献   
17.
18.
Anti-carcinoembryonic antigen monoclonal antibody (MAb) CEA102 was produced by immunization with purified CEA and the specific accumulation of radiolabeled CEA102 in colorectal cancers was investigated by autoradiography of surgical specimens using Fuji Computed Radiography (FCR). Five patients with colorectal cancer were injected intravenously with 131I-labeled intact CEA102 or its F(ab')2. Primary tumor and liver metastases were successfully detected by external scanning with a gamma camera in 4 cases. Autoradiographic study of the surgical specimens using FCR showed predominant localization of 131I-labeled CEA102 in primary tumors and liver metastases in all cases. Even a small liver metastasis (0.5 cm) was clearly visualized in the autoradiogram by FCR. The pixel distribution curves of the density of the respective tissues in the autoradiograms by FCR showed the heterogeneity of the distribution of administered radiolabeled MAb in individual tumors, but the density of the tumors was higher than that of the normal tissues. In the quantitative distribution analysis of CEA102, the uptake of the primary tumor (mean 1.10%ID/kg) was ten-fold greater than that of the normal colon mucosa (mean G.10%ID/kg). These results revealed that the application of MAb has great potential in radioimmunodetection as well as in antibody-directed therapy.  相似文献   
19.
20.
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