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   1457363篇
  免费   113435篇
  国内免费   2568篇
耳鼻咽喉   20354篇
儿科学   49179篇
妇产科学   38638篇
基础医学   205763篇
口腔科学   37713篇
临床医学   128663篇
内科学   295808篇
皮肤病学   30359篇
神经病学   118265篇
特种医学   57147篇
外国民族医学   673篇
外科学   224281篇
综合类   30042篇
现状与发展   3篇
一般理论   656篇
预防医学   112605篇
眼科学   31740篇
药学   107328篇
  3篇
中国医学   2756篇
肿瘤学   81390篇
  2019年   11951篇
  2018年   16522篇
  2017年   12712篇
  2016年   13783篇
  2015年   15854篇
  2014年   22399篇
  2013年   33870篇
  2012年   47166篇
  2011年   50329篇
  2010年   29878篇
  2009年   28109篇
  2008年   48333篇
  2007年   51694篇
  2006年   51521篇
  2005年   50845篇
  2004年   49678篇
  2003年   47693篇
  2002年   46688篇
  2001年   65655篇
  2000年   67768篇
  1999年   58198篇
  1998年   17590篇
  1997年   15846篇
  1996年   16079篇
  1995年   15153篇
  1994年   14318篇
  1993年   13275篇
  1992年   45609篇
  1991年   44477篇
  1990年   43153篇
  1989年   40969篇
  1988年   37798篇
  1987年   37136篇
  1986年   34505篇
  1985年   33247篇
  1984年   25458篇
  1983年   21594篇
  1982年   13356篇
  1981年   12160篇
  1980年   10928篇
  1979年   22079篇
  1978年   15697篇
  1977年   13388篇
  1976年   12454篇
  1975年   13256篇
  1974年   15246篇
  1973年   14644篇
  1972年   13321篇
  1971年   12034篇
  1970年   11331篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
Molnár  B.  Aroca  S.  Dobos  A.  Orbán  K.  Szabó  J.  Windisch  P.  Stähli  A.  Sculean  A. 《Clinical oral investigations》2022,26(12):7135-7142
Clinical Oral Investigations - To evaluate t he long-term outcomes following treatment of RT 1 multiple adjacent gingival recessions (MAGR) using the modified coronally advanced tunnel (MCAT) with...  相似文献   
2.
3.
4.
5.
6.
7.
8.
Amacrine cells of the retina are conspicuously variable in their morphologies, their population demographics, and their ensuing functions. Vesicular glutamate transporter 3 (VGluT3) amacrine cells are a recently characterized type of amacrine cell exhibiting local dendritic autonomy. The present analysis has examined three features of this VGluT3 population, including their density, local distribution, and dendritic spread, to discern the extent to which these are interrelated, using male and female mice. We first demonstrate that Bax-mediated cell death transforms the mosaic of VGluT3 cells from a random distribution into a regular mosaic. We subsequently examine the relationship between cell density and mosaic regularity across recombinant inbred strains of mice, finding that, although both traits vary across the strains, they exhibit minimal covariation. Other genetic determinants must therefore contribute independently to final cell number and to mosaic order. Using a conditional KO approach, we further demonstrate that Bax acts via the bipolar cell population, rather than cell-intrinsically, to control VGluT3 cell number. Finally, we consider the relationship between the dendritic arbors of single VGluT3 cells and the distribution of their homotypic neighbors. Dendritic field area was found to be independent of Voronoi domain area, while dendritic coverage of single cells was not conserved, simply increasing with the size of the dendritic field. Bax-KO retinas exhibited a threefold increase in dendritic coverage. Each cell, however, contributed less dendrites at each depth within the plexus, intermingling their processes with those of neighboring cells to approximate a constant volumetric density, yielding a uniformity in process coverage across the population.SIGNIFICANCE STATEMENT Different types of retinal neuron spread their processes across the surface of the retina to achieve a degree of dendritic coverage that is characteristic of each type. Many of these types achieve a constant coverage by varying their dendritic field area inversely with the local density of like-type neighbors. Here we report a population of retinal amacrine cells that do not develop dendritic arbors in relation to the spatial positioning of such homotypic neighbors; rather, this cell type modulates the extent of its dendritic branching when faced with a variable number of overlapping dendritic fields to approximate a uniformity in dendritic density across the retina.  相似文献   
9.
10.
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.  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