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   6715篇
  免费   312篇
  国内免费   75篇
耳鼻咽喉   43篇
儿科学   84篇
妇产科学   69篇
基础医学   985篇
口腔科学   126篇
临床医学   367篇
内科学   1756篇
皮肤病学   59篇
神经病学   478篇
特种医学   389篇
外科学   1240篇
综合类   35篇
预防医学   209篇
眼科学   42篇
药学   410篇
中国医学   18篇
肿瘤学   792篇
  2023年   46篇
  2022年   96篇
  2021年   127篇
  2020年   72篇
  2019年   109篇
  2018年   131篇
  2017年   131篇
  2016年   137篇
  2015年   130篇
  2014年   182篇
  2013年   209篇
  2012年   335篇
  2011年   365篇
  2010年   251篇
  2009年   200篇
  2008年   364篇
  2007年   423篇
  2006年   394篇
  2005年   399篇
  2004年   383篇
  2003年   378篇
  2002年   384篇
  2001年   166篇
  2000年   153篇
  1999年   145篇
  1998年   91篇
  1997年   77篇
  1996年   72篇
  1995年   65篇
  1994年   74篇
  1993年   76篇
  1992年   88篇
  1991年   96篇
  1990年   62篇
  1989年   68篇
  1988年   43篇
  1987年   70篇
  1986年   70篇
  1985年   47篇
  1984年   50篇
  1983年   32篇
  1982年   31篇
  1981年   41篇
  1980年   33篇
  1979年   32篇
  1978年   21篇
  1977年   20篇
  1974年   16篇
  1973年   20篇
  1966年   14篇
排序方式: 共有7102条查询结果,搜索用时 0 毫秒
21.
22.
23.
24.
25.
Summary.  Following establishment, via the vaginal route, of infection with an AP-1 binding-site deleted mutant (ΔAP-1) of feline immunodeficiency virus (FIV), cats were challenged with a homologous intact strain (TM2) of FIV. The cats were observed for 23 weeks to evaluate the efficacy of the ΔAP-1 against the homologous TM2 strain challenge. These two viruses were differentiated by Southern blotting after amplification of proviral DNA by semi-nested polymerase chain reaction in DNAs of peripheral blood mononuclear cells and tissues. A TM2-specific band was detected in one cat exposed to but not infected with ΔAP-1, but not in two ΔAP-1-infected. These results indicate that ΔAP-1 could protect against subsequent challenge with homologous FIV TM2 strain. Received December 23, 1998 Accepted March 31, 1998  相似文献   
26.
27.
The microwave tissue coagulator (MTC) is used in hepatectomy because it provides excellent haemostasis during the procedure. A 59 year old man underwent partial hepatic lobectomy with MTC, for metastasis from colon cancer. A tumorous necrotic nodule was discovered in the liver. The nodule measured 2.5 cm at its largest diameter. Microscopically, it showed extensive coagulation necrosis and massive sinusoidal dilatation. To date, such a necrotic mass clinically mimicking neoplasm has not been reported as a complication of hepatectomy using MTC. Although it is unknown how the rounded necrotic nodule was formed in this case, clinicians should be aware of this phenomenon to avoid unnecessary operations. Likewise, pathologists should recognise such histological changes and review the clinical history of the patient when coagulation necrosis with massive sinusoidal dilatation is observed in a biopsy or hepatectomy specimen.  相似文献   
28.
The inhibitory effect of an antiserum to surface protein P50 of Babesia gibsoni on the growth of the parasite was determined with severe combined immunodeficiency mice given canine red blood cells. The antiserum to the recombinant P50 protein significantly inhibited the parasite growth, indicating that P50 might be a useful vaccine candidate.  相似文献   
29.
Summary To investigate whether the feline CD 4 (fCD 4) molecules are involved in infections of highly lymphotropic feline immunodeficiency virus (FIV) isolates, we expressed fCD 4 stably on Crandell feline kidney cells andFelis catus whole foetus 4 cells by transfection of a cDNA encoding the fCD 4 glycoprotein, and then infected them with TM 1 and TM 2 strains of FIV, which are unable to infect these cells productively. In spite of fCD 4 being expressed on these cells, no virus production was observed. This result indicates that fCD 4 expression alone cannot induce a productive infection of the FIV TM 1 and TM 2 strains.  相似文献   
30.
The HIV/AIDS surveillance system in Japan, which began collecting data on the number of AIDS patients in 1984 and the number of HIV-infected persons in 1987, has played an important role in monitoring the trend and magnitude of Japan's HIV/AIDS epidemic and its distribution across various population subgroups. However, the system lacks any personal identifiers, making it impossible to eliminate duplication or to track cases for disease progression. It also does not permit the identification of the residence of HIV-infected persons because the residence of only the reporting physician is documented under the New Infectious Diseases Control Law, effective since April 1, 1999. The number of people with HIV/AIDS in Japan continues to grow. Among youth, sexually transmitted diseases, induced abortion, and sexual activities have shown a marked increase since the mid-1990s. Behavioral risk of infection for both injection drug users (IDUs) and men who have sex with men (MSM) remains alarmingly high. Accurate monitoring of infection rates is critical to the planning and evaluation of treatment, care and prevention programs. Japan should restructure its HIV/AIDS surveillance system to more accurately monitor the HIV/AIDS epidemic and related risk behaviors.  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