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   27090篇
  免费   1498篇
  国内免费   525篇
耳鼻咽喉   395篇
儿科学   655篇
妇产科学   588篇
基础医学   4585篇
口腔科学   572篇
临床医学   2158篇
内科学   3533篇
皮肤病学   749篇
神经病学   1976篇
特种医学   2104篇
外科学   3365篇
综合类   1627篇
现状与发展   2篇
一般理论   2篇
预防医学   2096篇
眼科学   400篇
药学   2628篇
  4篇
中国医学   652篇
肿瘤学   1022篇
  2023年   250篇
  2022年   369篇
  2021年   568篇
  2020年   465篇
  2019年   493篇
  2018年   729篇
  2017年   617篇
  2016年   696篇
  2015年   743篇
  2014年   1042篇
  2013年   1420篇
  2012年   1924篇
  2011年   2228篇
  2010年   1311篇
  2009年   769篇
  2008年   1418篇
  2007年   1599篇
  2006年   1567篇
  2005年   1316篇
  2004年   1308篇
  2003年   1373篇
  2002年   1154篇
  2001年   872篇
  2000年   907篇
  1999年   570篇
  1998年   250篇
  1997年   216篇
  1996年   157篇
  1995年   137篇
  1994年   104篇
  1993年   75篇
  1992年   118篇
  1991年   114篇
  1990年   130篇
  1989年   120篇
  1988年   107篇
  1987年   72篇
  1986年   79篇
  1985年   103篇
  1984年   90篇
  1983年   72篇
  1982年   77篇
  1981年   74篇
  1980年   61篇
  1979年   77篇
  1978年   69篇
  1977年   70篇
  1976年   59篇
  1975年   71篇
  1973年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Procedures for flow cytometric analysis and sorting of mitotic chromosomes (flow cytogenetics) have been developed for chickpea (Cicer arietinum). Suspensions of intact chromosomes were prepared from root tips treated to achieve a high degree of metaphase synchrony. The optimal protocol consisted of a treatment of roots with 2mmol/L hydroxyurea for 18h, a 4.5-h recovery in hydroxyurea-free medium, 2h incubation with 10µmol/L oryzalin, and ice-water treatment overnight. This procedure resulted in an average metaphase index of 47%. Synchronized root tips were fixed in 2% formaldehyde for 20min, and chromosome suspensions prepared by mechanical homogenization of fixed root tips. More than 4×105 morphologically intact chromosomes could be isolated from 15 root tips. Flow cytometric analysis of DAPI-stained chromosomes resulted in histograms of relative fluorescence intensity (flow karyotypes) containing eight peaks, representing individual chromosomes and/or groups of chromosomes with a similar relative DNA content. Five peaks could be assigned to individual chromosomes (A, B, C, G, H). The purity of sorted chromosome fractions was high, and chromosomes B and H could be sorted with 100% purity. PCR on flow-sorted chromosome fractions with primers for sequence-tagged microsatellite site (STMS) markers permitted assignment of the genetic linkage group LG8 to the smallest chickpea chromosome H. This study extends the number of legume species for which flow cytogenetics is available, and demonstrates the potential of flow cytogenetics for genome mapping in chickpea.  相似文献   
102.
103.
104.
105.
106.
Anatomical variations in the dimensions of different brain structures have been correlated with clinical syndromes. This study on the parameters of normal and abnormal cavum septi pellucidi (CSP) can be of clinical significance. We obtained 479 brains from autopsied persons (310 males and 169 females, 377 normal or asymptomatic and 102 abnormal or symptomatic persons, aged 22-89 years) and observed that 110 brains (75 males and 35 females) had CSP. These cava were classified into two groups depending on the past medical histories of the autopsied person: 40 asymptomatic and 70 symptomatic cava. We have defined symptomatic cava as those in autopsied persons who had known past medical history of psychiatric or neurological disease. Asymptomatic cava were in autopsied persons who had no known past medical history of psychiatric or neurological disease. The CSP parameters (length, width, depth) of the symptomatic and asymptomatic groups were measured and were statistically analyzed. Analysis showed that the cava in the symptomatic group were significantly longer and wider. Discriminant function analysis was used to derive a mathematical formula to classify CSP into an asymptomatic or symptomatic group based on length and width measurements of the cavum.  相似文献   
107.
108.
109.
110.
In our series of 136 patients with primary total knee arthroplasty using posterior-stabilized prosthesis, a female patient with Parkinson disease developed posterior dislocation of the knee 9 months after surgery. Eventually, the dislocation became recurrent, occurring several times a day. The patient made the reposition always by herself. Two months after the first dislocation, we performed the revision of the polyethylene tibial insert and found wearing of the tibial insert's cam as an hitherto unreported cause of the mechanical instability of the total knee prosthesis.  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