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   3307篇
  免费   406篇
  国内免费   1篇
耳鼻咽喉   29篇
儿科学   225篇
妇产科学   57篇
基础医学   443篇
口腔科学   158篇
临床医学   358篇
内科学   786篇
皮肤病学   28篇
神经病学   370篇
特种医学   82篇
外科学   321篇
综合类   94篇
一般理论   4篇
预防医学   298篇
眼科学   31篇
药学   269篇
中国医学   6篇
肿瘤学   155篇
  2021年   41篇
  2019年   37篇
  2018年   47篇
  2017年   35篇
  2016年   32篇
  2015年   49篇
  2014年   43篇
  2013年   86篇
  2012年   115篇
  2011年   119篇
  2010年   67篇
  2009年   59篇
  2008年   128篇
  2007年   113篇
  2006年   122篇
  2005年   118篇
  2004年   118篇
  2003年   120篇
  2002年   112篇
  2001年   115篇
  2000年   86篇
  1999年   101篇
  1998年   38篇
  1997年   52篇
  1996年   36篇
  1995年   38篇
  1993年   30篇
  1992年   74篇
  1991年   94篇
  1990年   75篇
  1989年   82篇
  1988年   85篇
  1987年   98篇
  1986年   78篇
  1985年   80篇
  1984年   58篇
  1983年   54篇
  1982年   44篇
  1980年   46篇
  1979年   71篇
  1978年   58篇
  1977年   50篇
  1976年   35篇
  1975年   40篇
  1974年   47篇
  1973年   42篇
  1972年   37篇
  1970年   38篇
  1969年   40篇
  1967年   27篇
排序方式: 共有3714条查询结果,搜索用时 15 毫秒
21.
Nineteen patients, aged 60 years and over, with rheumatoid arthritis participated in a clinical trial to investigate the pharmacokinetics of isoxicam (a new non-steroidal anti-inflammatory drug) in this age group. The purpose of the study was to determine if the pharmacokinetics are different compared to a younger healthy population. The half-lives were independent of dosage, indicating linearity of pharmacokinetics. Furthermore, the half-lives after repeated dosing were not different from those found after single doses of 400 mg. This shows that there is neither undue accumulation of the drug nor induction of its own metabolism. These results are similar to the results obtained in other centres when isoxicam was administered to healthy subjects between 18 and 32 years.  相似文献   
22.
23.
A number of variables affect the result of the bleeding time, the most frequently used test assessing primary hemostasis. Although the test is now usually performed with one of several commercially available disposable devices, most previous studies of the bleeding time have evaluated only the original template device described nearly 20 years ago. Therefore, we compared two commonly used bleeding time devices (Surgicutt and Simplate) with regard to multiple variables affecting the test in 40 hematologically normal young adults. Bleeding time was performed by the modified Ivy method according to the manufacturers' instructions in both horizontal (transverse) and vertical directions, before and two hours after a test dose of 650 mg of aspirin was administered. With both horizontal and vertical incisions, Simplate bleeding time values were greater than with the Surgicutt device (P = 0.0025). Bleeding time in the horizontal direction was greater than vertical with both devices (P = 0.0001). Values in males and females were not significantly different. Aspirin sensitivity, the difference between preaspirin and postaspirin values, was greatest with the use of the Surgicutt device in the horizontal position (mean postaspirin value 8.0 minutes). Both devices produced a reproducible uniform incision, caused minimal discomfort, and resulted in little or no scarring. The authors conclude that the results with Surgicutt and Simplate devices were comparable in many respects but that a horizontal Surgicutt bleeding time might be most sensitive in detecting disorders of primary hemostasis. Comparative studies of different bleeding time devices in normal subjects are necessary in order to accurately assess their clinical utility.  相似文献   
24.
25.
26.
BACKGROUND: An antibody method based on absorption of serum with cytomegalovirus (CMV) glycoprotein B (gB) was developed for detection of infection during clinical trials of CMV gB vaccine. Previous study showed that this method detected the antibody response to infection and was negative with vaccine induced immunity. OBJECTIVES: In an ongoing efficacy trial of CMV gB vaccine the ability of the gB-absorbed CMV IgG assay to detect CMV infection was assessed and compared with viral culture results. STUDY DESIGN: Two hundred and ninety two healthy, seronegative young women in a phase II, double-blind, placebo-controlled, clinical trial of recombinant CMV gB vaccine (sanofi pasteur) with MF59 adjuvant (Chiron) were randomized to receive CMV gB vaccine or placebo (1:1) on a 0, 1 and 6 month schedule. Participants were screened every 3 months for CMV infection using the gB-absorbed CMV IgG assay, and a subgroup was also screened for infection with viral cultures. Viral culture (urine, vaginal swab and saliva) was used to confirm CMV infection in all subjects with a positive gB-absorbed CMV IgG result. RESULTS: Evidence of CMV infection (gB-absorbed CMV IgG levels>or=5.0 AU/ml) was found in 23/292 (7.88%) study participants. The gB-absorbed CMV IgG levels of their first positive serum ranged from 15.7 to 251.0 AU/ml with a mean of 77.0 AU/ml and a median of 44.9 AU/ml. Cytomegalovirus was isolated from all 23 of them from culture specimens collected after their first positive gB-absorbed CMV IgG. The time to first CMV positive culture from first positive gB-absorbed CMV IgG ranged from 0 to 12 weeks with a median of 2 weeks. CONCLUSIONS: The gB-absorbed CMV IgG assay detects CMV infection in CMV gB vaccine clinical trials earlier and more rapidly than virus culture and does not reveal whether subjects received CMV gB vaccine or placebo.  相似文献   
27.
Eight male baboons inoculated intraurethrally with Neisseria gonorrhoeae failed to shed gonococci or develop serum antibody. Urethral inoculation, preceded by epididymal inoculation, elicited an anamnestic antibody response.  相似文献   
28.
Several groups have reported an association between schizophrenia and the MscI polymorphism in the first exon of the dopamine D3 receptor gene (DRD3). We studied this polymorphism using a North American sample (117 patients plus 188 controls) and an Italian sample (97 patients plus 64 controls). In the first part of the study, we compared allele frequencies of schizophrenia patients and unmatched controls and observed a significant difference in the total sample (P = 0.01). The second part of the study involved a case control approach in which each schizophrenia patient was matched to a control of the same sex, and of similar age and ethnic background. The DRD3 allele frequencies of patients and controls revealed no significant difference between the two groups in the Italian (N = 53) or the North American (N = 54) matched populations; however, when these two matched samples were combined, a significant difference was observed (P = 0.026). Our results suggest that the MscI polymorphism may be associated with schizophrenia in the populations studied. © 1995 Wiley-Liss, Inc.  相似文献   
29.
Monoclonal antibodies directed to six separate antigen molecules of Mycobacterium leprae have been tested in an antigen-capture assay based on combined use of polyclonal ("capture") and monoclonal ("detector") antibody reagents. This approach provides a potentially versatile, sensitive and specific assay for detection and relative quantitation of M. leprae antigens. Characterisation of monoclonal antibodies to mycobacterial lipoarabinomannan (LAM-B) by the antigen-capture assay indicates that some of the antigenic determinants present on LAM-B from M. leprae may be either absent altogether or present at much lower concentrations on the corresponding LAM-B structure form M. tuberculosis.  相似文献   
30.
A three-dimensional (3-D) lung aggregate model was developed from A549 human lung epithelial cells by using a rotating-wall vessel bioreactor to study the interactions between Pseudomonas aeruginosa and lung epithelial cells. The suitability of the 3-D aggregates as an infection model was examined by immunohistochemistry, adherence and invasion assays, scanning electron microscopy, and cytokine and mucoglycoprotein production. Immunohistochemical characterization of the 3-D A549 aggregates showed increased expression of epithelial cell-specific markers and decreased expression of cancer-specific markers compared to their monolayer counterparts. Immunohistochemistry of junctional markers on A549 3-D cells revealed that these cells formed tight junctions and polarity, in contrast to the cells grown as monolayers. Additionally, the 3-D aggregates stained positively for the production of mucoglycoprotein while the monolayers showed no indication of staining. Moreover, mucin-specific antibodies to MUC1 and MUC5A bound with greater affinity to 3-D aggregates than to the monolayers. P. aeruginosa attached to and penetrated A549 monolayers significantly more than the same cells grown as 3-D aggregates. Scanning electron microscopy of A549 cells grown as monolayers and 3-D aggregates infected with P. aeruginosa showed that monolayers detached from the surface of the culture plate postinfection, in contrast to the 3-D aggregates, which remained attached to the microcarrier beads. In response to infection, proinflammatory cytokine levels were elevated for the 3-D A549 aggregates compared to monolayer controls. These findings suggest that A549 lung cells grown as 3-D aggregates may represent a more physiologically relevant model to examine the interactions between P. aeruginosa and the lung epithelium during infection.  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