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   12642篇
  免费   1001篇
  国内免费   53篇
耳鼻咽喉   123篇
儿科学   445篇
妇产科学   251篇
基础医学   1832篇
口腔科学   317篇
临床医学   1234篇
内科学   2437篇
皮肤病学   130篇
神经病学   813篇
特种医学   860篇
外国民族医学   2篇
外科学   1814篇
综合类   233篇
一般理论   20篇
预防医学   1153篇
眼科学   356篇
药学   786篇
中国医学   15篇
肿瘤学   875篇
  2022年   77篇
  2021年   185篇
  2020年   81篇
  2019年   156篇
  2018年   209篇
  2017年   140篇
  2016年   164篇
  2015年   208篇
  2014年   286篇
  2013年   440篇
  2012年   575篇
  2011年   607篇
  2010年   469篇
  2009年   425篇
  2008年   586篇
  2007年   635篇
  2006年   588篇
  2005年   633篇
  2004年   588篇
  2003年   514篇
  2002年   536篇
  2001年   280篇
  2000年   310篇
  1999年   261篇
  1998年   270篇
  1997年   238篇
  1996年   223篇
  1995年   187篇
  1994年   170篇
  1993年   172篇
  1992年   205篇
  1991年   176篇
  1990年   175篇
  1989年   232篇
  1988年   189篇
  1987年   196篇
  1986年   176篇
  1985年   190篇
  1984年   148篇
  1983年   153篇
  1982年   118篇
  1981年   110篇
  1980年   118篇
  1979年   123篇
  1978年   122篇
  1977年   83篇
  1976年   102篇
  1975年   100篇
  1974年   80篇
  1973年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Neurotensin(8-13), the carboxyl-terminal portion of neurotensin, is 4-50 times more potent than native neurotensin in binding to intact neuroblastoma N1E-115 cells and human brain tissue and in stimulation of intracellular cyclic GMP production and inositol phospholipid hydrolysis in clone N1E-115 (Gilbert JA and Richelson E, Eur J Pharmacol 99: 245-246, 1984; Gilbert JA et al., Biochem Pharmacol 35: 391-397, 1986; Kanba KS et al., J Neurochem 46: 946-952, 1986; and Kanba KS and Richelson E, Biochem Pharmacol 36: 869-874, 1987). A series of novel analogs of neurotensin (8-13) was synthesized, and a structure-activity study was done comparing the abilities of these peptides to stimulate intracellular cyclic GMP production in intact neuroblastoma clone N1E-115 and to inhibit the binding of [3H]neurotensin to these cells and to membranal preparations from human brain. A direct correlation was found for each analog between its EC50 for biochemical activity and its KD for binding ability in studies with clone N1E-115. Furthermore, a strong correlation existed for each peptide between its KD for binding to neurotensin receptors on these cells and its KD for binding to neurotensin receptors in human brain tissue. In this study, the residues that were important to the biochemical and binding activities of neurotensin (8-13) proved to be identical to the amino acids that are necessary for the functional integrity of native neurotensin (Gilbert JA et al., Biochem Pharmacol 35: 391-397, 1986.  相似文献   
992.
993.
Childhood scoliosis: MR imaging   总被引:2,自引:0,他引:2  
The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography.  相似文献   
994.
995.
996.
AIMS: To describe trends of responses to the Cut-down, Annoyed, Guilt, Eye-opener (CAGE) questionnaire during a period of declining alcohol consumption, in a country with no temperance history. DESIGN: Two random-sample surveys, conducted in 1991 and 2005, respectively. SETTING: The adult population of Ile-de-France. PARTICIPANTS: A total of 1183 subjects in 1991 and 5382 subjects in 2005. MEASUREMENTS: Responses to CAGE questions, obtained by face-to-face interviews in 1991 and by telephone in 2005. RESULTS: were standardized on the 2005 population structure. FINDINGS: The proportion of subjects giving at least two positive answers has increased by 4.2 times; the biggest increase was observed for the Guilt question (4.8 times) and the smallest for the Eye-opener question (2.6 times). Several increases were higher for women than for men: 12.9 times versus 3.3 times for two or more positive answers, 9.8 times versus 3.8 times for the Guilt question. Increases did not vary consistently by age. CONCLUSION: These paradoxical trends do not support the use of CAGE in general population surveys. They confirm previous reports suggesting that CAGE was sensitive to community temperance level. They might reflect the emergence of a temperance movement in France, with stronger impact among women. This movement might be responsible for the fall in alcohol consumption.  相似文献   
997.
This pilot study examined whether refusal assertion as defined by a proven drug prevention program was associated with adolescent perceptions of effectiveness by comparing two sets of coded responses to adolescent videotaped refusal role-plays (N = 63). The original set of codes was defined by programmatic standards of refusal assertion and the second by a group of high school interns. Consistency with programming criteria was found for interns’ ratings of several indicators of verbal and non-verbal assertiveness. However, a strategy previously defined by the program as effective was perceived as ineffective by adolescents while another deemed ineffective and problematic by intervention developers was viewed as effective. Interns endorsed presenting detailed and reasonable arguments as an effective refusal strategy while short, simple statements were deemed ineffective. This study suggests the importance of including adolescent perspectives in the design, delivery, and evaluation of drug prevention strategies.  相似文献   
998.
The drug development process is dependent upon having established end points for measuring drug efficacy and adverse effects. New drug development in organ transplantation suffers from having end points which are either outdated or which do not serve the purpose of addressing the current critical drug therapy problems. Numerous biomarkers have been examined in organ transplantation, but almost all would be classified as exploratory for drug development purposes. Some of the possible pathways out of this dilemma include investigator- or consortium-initiated research that would qualify the biomarkers as either probable or known valid biomarkers, help in identification of new end points in transplantation and their associated biomarkers, co-development of a new biomarker and drug for transplantation and the use of new clinical trial design methods which facilitate enriched or stratified transplant patient populations. With new biomarkers and new study design methodologies for drug development, improvement in the drug development process for transplantation is a real possibility that the transplant clinical and research community can help to bring about.  相似文献   
999.
1000.

Background  

Ablation of the left atrium and pulmonary veins antrum (PVAI) can be an effective treatment of atrial fibrillation (AF). However, there is discrepancy in the literature regarding the effect extensive ablation has on left atrial (LA) function. We sought to evaluate the effect that AF ablation procedures has on global and regional wall motion as assessed by cardiovascular magnetic resonance imaging (MRI).  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