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   150672篇
  免费   7569篇
  国内免费   143篇
耳鼻咽喉   2339篇
儿科学   5088篇
妇产科学   3393篇
基础医学   22304篇
口腔科学   4865篇
临床医学   12920篇
内科学   27701篇
皮肤病学   4088篇
神经病学   15304篇
特种医学   6279篇
外科学   22953篇
综合类   717篇
一般理论   50篇
预防医学   8607篇
眼科学   3298篇
药学   10280篇
中国医学   217篇
肿瘤学   7981篇
  2023年   894篇
  2022年   605篇
  2021年   1475篇
  2020年   1376篇
  2019年   1701篇
  2018年   3294篇
  2017年   2796篇
  2016年   3616篇
  2015年   3179篇
  2014年   3566篇
  2013年   6159篇
  2012年   7857篇
  2011年   8742篇
  2010年   4924篇
  2009年   3518篇
  2008年   8745篇
  2007年   9224篇
  2006年   8909篇
  2005年   8711篇
  2004年   8228篇
  2003年   8222篇
  2002年   8103篇
  2001年   5417篇
  2000年   6840篇
  1999年   3886篇
  1998年   1625篇
  1997年   1361篇
  1996年   1063篇
  1995年   882篇
  1994年   871篇
  1993年   806篇
  1992年   891篇
  1991年   768篇
  1990年   742篇
  1989年   747篇
  1988年   644篇
  1987年   691篇
  1986年   631篇
  1985年   834篇
  1984年   773篇
  1983年   663篇
  1982年   702篇
  1981年   618篇
  1980年   575篇
  1979年   568篇
  1978年   497篇
  1977年   523篇
  1976年   450篇
  1975年   440篇
  1974年   424篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Medical records of 158 patients with bipolar depression were analysed for the incidence of a switch from depression to maniform states (mania and hypomania). Relation to psychopharmacological treatment was investigated. Thirty-nine (25%) patients of the total sample had switched to a maniform state during the treatment period in the hospital. Among that group the phenomenon occurred in 23 patients (15%) as a hypomania and in 16 patients (10%) as a mania. Patients with a switch were significantly more often treated with tricyclic antidepressants (TCA) than patients without switch (79.5% vs 51.3%). Mood stabilising medication might reduce the risk for switching, especially in patients treated with TCA; however, it seems not totally sufficient, since 59% of the switched patients received mood stabilisers. The switch phenomenon was not associated with sociodemographic or clinical data. Received: 23 September 1998 / Accepted: 28 September 1998  相似文献   
82.
One hundred and one patients, nursed in an intensive care unit for at least 24h, were monitored for bacterial colonization and infection. The infection rates were similar to those in other reports. Patients were not generally colonized with common environmental strains in the unit. Bacterial dissemination between patients was uncommon. No gentamicin resistant gram negative or Staphylococcus aureus strains were observed, nor methicillin resistant Staphylococcus aureus strains. the hypothesis that these favourable conditions are partly related to the excellent isolation and barrier nursing facilities in the unit cannot be fully substantiated.  相似文献   
83.
Summary Silanated slides provide excellent tissue adhesion for routine histology, immunhistochemistry and in situ hybridization of frozen, paraffin embedded material or cell smears. An easy and inexpensive method of treating glass microscope slides with triethoxysilylpropylamine is reported.  相似文献   
84.
An extrachromosomal nucleic acid element was detected in high-molecular-weight DNA preparations formBabesia equi merozoites. This extrachromosomal element was shown to be DNA rather than RNA and had an apparent fragment size of about 9 kilobasepairs (kb). Hybridization experiments using purified 9-kb DNA as a probe revealed sequence homologies with extrachromosomal DNA from two otherBabesia species.  相似文献   
85.
86.
In three groups of six mice each, the α- and β-receptors were blocked by phentolamine and propranolol. The mice in the three groups then received an intravenous bolus injection of saline solution, epinephrine, and insulin, respectively. Cortical bone capillaries from the tibia diaphysis were submitted to transmission electron microscopy (TEM). The lumen and endothelium were measured and the results compared. Significant changes were only noted in the endothelium after the administration of insulin. These findings suggest that there are also insulin receptors in bone. Furthermore, they support previous findings in similar studies with epinephrine.  相似文献   
87.
88.
89.
The objective of the study was to assess scintigraphic patterns and femoral shortening after femoral neck fracture in order to select predictive parameters for late complications. Eighty-eight patients with osteosynthesized femoral neck fractures were followed for 2 years with regular scintigraphic evaluations and orthoradiographic measurements of femoral length shortening. Four different patient categories were identified with regard to the late outcome: two different groups with uneventful healing and two different groups with late complications. Accordingly, a high scintigraphic uptake at 1 month may eiher point to an uneventful healing if combined with minor femoral shortening or indicate failure if combined with a high degree of femoral shortening. In contrast, low scintigraphic uptake may either reflect primary fracture healing if accompanied by minor femoral shortening or predict failure if a high degree of femoral shortening is present. Compared with using scintigraphy alone, combined scintigraphic evaluation and assessment of femoral shortening increased the accuracy for prediction of late failures from 80% to 93%. Early scintigraphic patterns after osteosynthesis of femoral neck fractures have to be validated with care. Radiographic assessment of femoral shortening, which is less invasive, gives better prognostic accuracy and should therefore be preferred for this purpose.  相似文献   
90.
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