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   14154篇
  免费   1339篇
  国内免费   17篇
耳鼻咽喉   157篇
儿科学   434篇
妇产科学   301篇
基础医学   1790篇
口腔科学   294篇
临床医学   1740篇
内科学   2840篇
皮肤病学   220篇
神经病学   1400篇
特种医学   562篇
外科学   2009篇
综合类   267篇
一般理论   12篇
预防医学   1422篇
眼科学   307篇
药学   949篇
中国医学   19篇
肿瘤学   787篇
  2021年   216篇
  2020年   130篇
  2019年   215篇
  2018年   264篇
  2017年   212篇
  2016年   235篇
  2015年   235篇
  2014年   317篇
  2013年   500篇
  2012年   663篇
  2011年   679篇
  2010年   364篇
  2009年   391篇
  2008年   617篇
  2007年   662篇
  2006年   716篇
  2005年   620篇
  2004年   607篇
  2003年   530篇
  2002年   503篇
  2001年   488篇
  2000年   474篇
  1999年   399篇
  1998年   145篇
  1997年   137篇
  1996年   116篇
  1995年   126篇
  1994年   114篇
  1992年   283篇
  1991年   289篇
  1990年   326篇
  1989年   276篇
  1988年   234篇
  1987年   230篇
  1986年   244篇
  1985年   221篇
  1984年   194篇
  1983年   159篇
  1982年   119篇
  1980年   97篇
  1979年   151篇
  1978年   127篇
  1977年   121篇
  1976年   133篇
  1975年   97篇
  1974年   126篇
  1973年   99篇
  1972年   118篇
  1971年   98篇
  1970年   103篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Laterality of cross-modal spatial processing   总被引:1,自引:0,他引:1  
This study examined the laterality of spatial-form perception in normal adults using a cross-modal matching paradigm involving visual and tactile processing. Randomly generated eight-point and 12-point Vanderplas and Garvin (1959) patterns were used as the stimuli. In a visual-to-tactile task, a lateralized visual pattern was followed immediately by a haptic task requiring subjects to discriminate which of two simultaneously felt shapes matched the visual pattern. In a tactile-to-visual task, subjects decided which of two simultaneously felt shapes matched a lateralized visual pattern presented after haptic manipulation. There were no main effects for laterality or for sex differences. Matching accuracy was better in the visual-to-tactile task and for less complex stimuli. A visual field by feeling hand interaction showed best recognition accuracy when visual-feeling hand combinations on the same side of the body were used in the two matching tasks. These data reflect a stimulus-response compatibility explanation of spatial-form perception that is consistent with a behavioral and not a cerebral asymmetry model.  相似文献   
3.
4.
5.
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use.  相似文献   
6.
7.
8.
Chemically distinct rat olivocochlear neurons.   总被引:6,自引:0,他引:6  
We have produced a neurochemical map of the cell bodies of origin of the cochlear efferent terminals in rat by combining glutamic acid decarboxylase (GAD), choline acetyltransferase (ChAT), or calcitonin gene-related peptide (CGRP) immunocytochemistry with retrograde transport of horseradish peroxidase. The locations of cochlear efferent cell bodies are in general agreement with the medial and lateral systems described by White and Warr (J. Comp. Neurol. 219:203-214, 1983) with some minor modifications. The lateral system consists of at least two pools of chemically distinct neurons located within the lateral superior olive (LSO) ipsilateral to the injected cochlea. One pool immunostains with an antibody to GAD while the other immunostains with antibodies to ChAT and to CGRP. The medial efferent system consists of periolivary neurons that are almost exclusively large and ChAT-positive but CGRP-negative. They are located both ipsilateral and contralateral to the cochlea they project to. There are a few GAD-positive small neurons in the medioventral and rostral periolivary regions that project ipsilaterally, but these may prove tobe ectopic neurons. The ipsilateral lateroventral periolivary region (LVPO) contains some efferent neurons, all of which are ChAT-positive but CGRP-negative. Additional cochlear efferent neurons, some of which are ChAT-positive and others GAD-positive, are present within and immediately dorsal to the fiber capsule surrounding the medial limb, and to a lesser extent the lateral limb, of the ipsilateral LSO. Not all GAD-positive or ChAT-positive olivary cells project to the cochlea. We have complemented the results in the brainstem by demonstrating two immunocytochemically distinct populations of efferent terminals in the cochlea simultaneously, one CGRP-positive and the other GAD-positive. Approximately equal numbers of boutons immunoreactive for both markers are present beneath inner hair cells throughout the entire length of the cochlea. Surprisingly high numbers of GAD-positive and CGRP-positive boutons are also present on outer hair cells, with each class having its spatially and morphologically distinct features. The lack of CGRP-positive periolivary cells that are retrogradely labeled by cochlear injections of HRP suggests that the lateral olivocochlear system sends projections to outer hair cells. Our results raise questions about species differences in the organization of targets of the lateral and medial olivocochlear systems.  相似文献   
9.
Massive immune hemolysis due to passenger lymphocyte-derived anti-D has not been reported in renal transplantation. A 50-year-old (B-positive) male received a dual deceased-donor kidney transplant (B-negative) for diabetic renal failure. Two weeks post-transplant, the patient developed severe hemolytic anemia. The donor anti-D titer was 1:8. The recipient anti-D titer (zero pre-transplant) increased from 1:4 to 1:16 over 4 days. Rapid hemolysis caused severe anemia, minimum Hb = 4.2 g/dL, while selectively lysing the patient's autologous red cells during this time. The hemolytic anemia did not impair the allografts and subsided without monoclonal B-cell pharmacotherapy or apheresis. The anti-D titer decreased to barely detectable levels at four months and had cleared when checked 2 years post-transplant. Transfusion support subsided after two months. If complications of anemia can be avoided, the deleterious effects of hemolysis may be well tolerated by renal allografts using antigen negative transfusion alone.  相似文献   
10.
Pulmonary artery aneurysms are rare lesions for which operative management is not frequently undertaken. When operation is indicated, central lesions involving the pulmonary trunk, right main pulmonary artery, or left main pulmonary artery are repaired using cardiopulmonary bypass. Peripheral aneurysms in segmental intrapulmonary arteries have been managed most frequently by lobectomy, but occasionally by aneurysmectomy and pulmonary arterial repair. We used cardiopulmonary bypass for peripheral pulmonary aneurysmectomy in a patient with limited respiratory reserve because he had undergone prior contralateral bilobectomy; this allowed controlled resection while preserving a maximal amount of pulmonary parenchyma.  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