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   38026篇
  免费   2805篇
  国内免费   81篇
耳鼻咽喉   275篇
儿科学   902篇
妇产科学   773篇
基础医学   5136篇
口腔科学   896篇
临床医学   4585篇
内科学   6685篇
皮肤病学   593篇
神经病学   3491篇
特种医学   1488篇
外科学   5095篇
综合类   677篇
一般理论   45篇
预防医学   4622篇
眼科学   653篇
药学   2701篇
  1篇
中国医学   51篇
肿瘤学   2243篇
  2023年   209篇
  2022年   374篇
  2021年   738篇
  2020年   497篇
  2019年   727篇
  2018年   853篇
  2017年   645篇
  2016年   673篇
  2015年   855篇
  2014年   1130篇
  2013年   1566篇
  2012年   2449篇
  2011年   2485篇
  2010年   1443篇
  2009年   1333篇
  2008年   2153篇
  2007年   2319篇
  2006年   2122篇
  2005年   2129篇
  2004年   2092篇
  2003年   1989篇
  2002年   1782篇
  2001年   748篇
  2000年   767篇
  1999年   717篇
  1998年   446篇
  1997年   337篇
  1996年   353篇
  1995年   276篇
  1994年   254篇
  1993年   233篇
  1992年   482篇
  1991年   445篇
  1990年   432篇
  1989年   400篇
  1988年   337篇
  1987年   362篇
  1986年   317篇
  1985年   324篇
  1984年   304篇
  1983年   258篇
  1982年   153篇
  1980年   149篇
  1979年   203篇
  1978年   157篇
  1976年   139篇
  1975年   143篇
  1974年   144篇
  1973年   148篇
  1972年   150篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
41.
We analysed a group of 390 patients, diagnosed with chronic lymphocytic leukaemia (CLL). Cases were subclassified as morphologically typical and atypical CLL according to the criteria of the FAB proposal. Typical CLL cases were mostly diagnosed at a low-risk stage (Binet A/Rai 0), required no immediate treatment and expected a long survival; atypical CLL cases mostly presented at a more advanced risk stage (Binet B/Rai I–II), usually required immediate treatment and their survival was shorter. Moreover, clinical staging was of prognostic significance in typical but not in atypical cases.   In typical CLL, del(11q) was the most common chromosomal abnormality (21%) whereas in atypical CLL trisomy 12 was found in about 65% of the cases documented with an abnormal karyotype. Although chromosomal abnormalities were associated with a poor survival in typical CLL, they are of no prognostic significance in atypical CLL.   Based on these data, we conclude that subtyping CLL by morphology enables the identification of two groups of cases, each characterized by a specific clinical presentation, different cytogenetic abnormalities and prognostic parameters. We speculate that these two groups may represent two related, but different, diseases with different prognostic parameters and a different survival.  相似文献   
42.
43.
44.
45.
Broviac catheters are commonly used to provide parenteral nutrition and access for infusion of blood products and drugs to pediatric patients. Sepsis is the most common serious complication of continued catheter use. Although removal of the catheter is generally recommended when it becomes contaminated, it may not be feasible to do so without compromising patient care. We evaluated the management of catheter-related infections in pediatric patients with and without removal of catheter. Seventy-seven episodes of catheter sepsis were evaluated in 61 pediatric patients; 24 were neonates and 37 were older children. The catheters were used for multiple purposes in 75% of cases. The most common microorganisms isolated were Staphylococcus epidermidis in 26%, Klebsiella pneumoniae in 9%, and Streptococcus viridans in 8% of cases; other pathogens included group D Enterococcus, Staphylococcus aureus, and Escherichia coli. Pseudomonas aeruginosa was isolated in four older children. Thirty-five patients were treated with antibiotics without catheter removal. Thirty patients received appropriate antibiotic therapy based on the susceptibility data. Twenty-six of these 30 patients responded within 5 days of therapy whereas the others required 15-39 days of treatment. Lack of response was mainly associated with the presence of abscess, immunocompromised status, and organisms P. aeruginosa and Candida albicans. Based on the sensitivity and minimum inhibitory concentration data, a combined regimen of gentamicin and vancomycin would be an effective initial therapy. These findings suggest that (1) catheter sepsis can be managed with appropriate antibiotics, and (2) when continued use of Broviac catheter is desired, a trial of antibiotic therapy should be attempted before catheter removal.  相似文献   
46.
The potential cytoprotective actions of a novel nicotinic agent 2,4-dimethoxybenzilidene anabaseine (DMXB) were investigated in differentiated PC12 cells and transected rat septal cholinergic neurons in vivo. In NGF-differentiated PC12 cells, removal of both NGF and serum led to cell loss, a reduced % of cells expressing neurites, the release of lactate dehydrogenase, and a decrease in total cellular protein. Cell loss was apparent within 24 h, and remained constant between 4–8 days post-NGF removal. NGF alone (100 ng/ml), DMXB (10 μM), but not nicotine (10 μM), prevented these cell and neurite losses. DMXB-induced cytoprotection was blocked by 1 μM mecamylamine. DMXB (1 mg/kg, ip) injected twice but not once per day protected cholinesterase-staining septal neurons from retrograde degeneration following unilateral fimbrial transections. The twice per day DMXB injection-protocol also decreased cell roundness among cholinesterase-staining cells in the lesioned septal hemisphere compared to saline-injected animals. These studies suggest that DMXB may exert cytoprotective activity in NGF-sensitive neuronal populations. © 1994 Wiley-Liss, Inc.  相似文献   
47.
High-level language functioning was assessed in a group of 11 children with severe closed head injury (CHI). Performance was examined on measures of figurative language, oral expression, inferencing, and interpretation of ambiguous sentences, and was compared with that of a control group matched for age, gender, and handedness. The children with CHI demonstrated inferior performance on the oral expression, ambiguous sentences, and figurative language tests; however, performance on the inferencing task appeared intact. These findings are discussed with respect to the underlying nature of the observed impairments. Both linguistic and cognitive factors are considered. It is concluded that a complex interaction of cognitive and linguistic impairments experienced by children with CHI may underlie the performance deficits identified in the current study.  相似文献   
48.
The original article to which this Erratum refers was published in International Journal of Methods in Psychiatric Research, 2005; Vol.14, No.3, 158–166. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
49.
50.
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