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   10442篇
  免费   1091篇
  国内免费   78篇
耳鼻咽喉   94篇
儿科学   306篇
妇产科学   271篇
基础医学   1304篇
口腔科学   193篇
临床医学   1099篇
内科学   2337篇
皮肤病学   95篇
神经病学   766篇
特种医学   720篇
外国民族医学   1篇
外科学   1159篇
综合类   286篇
一般理论   2篇
预防医学   1317篇
眼科学   310篇
药学   773篇
中国医学   10篇
肿瘤学   568篇
  2021年   143篇
  2019年   146篇
  2018年   160篇
  2017年   101篇
  2016年   130篇
  2015年   150篇
  2014年   186篇
  2013年   350篇
  2012年   437篇
  2011年   482篇
  2010年   288篇
  2009年   255篇
  2008年   394篇
  2007年   520篇
  2006年   411篇
  2005年   432篇
  2004年   439篇
  2003年   406篇
  2002年   389篇
  2001年   326篇
  2000年   328篇
  1999年   282篇
  1998年   150篇
  1997年   129篇
  1996年   127篇
  1995年   130篇
  1994年   140篇
  1993年   101篇
  1992年   221篇
  1991年   226篇
  1990年   212篇
  1989年   225篇
  1988年   186篇
  1987年   215篇
  1986年   167篇
  1985年   185篇
  1984年   150篇
  1983年   146篇
  1982年   113篇
  1981年   118篇
  1980年   89篇
  1979年   122篇
  1978年   101篇
  1977年   92篇
  1976年   114篇
  1975年   112篇
  1974年   141篇
  1973年   121篇
  1972年   111篇
  1971年   89篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
71.
72.
73.
74.
Partial monosomy of 6q resulting from an interstitial deletion of bands q16----q22 was found in a 12-year-old boy manifesting mental retardation, seizure disorder, and dysmorphic features. The correlation of phenotypic expression and specific long arm deletions of chromosome No. 6 is discussed.  相似文献   
75.
Aerococci can be misidentified as streptococci, enterococci, pediococci, lactococci, or leuconostocs. To distinguish the genus and determine if another species is needed in the present taxon, we analyzed 37 aerococci for cellular fatty acids and compared them with 377 strains of gram-positive cocci, including the species type strains from each of the related genera. The cellular fatty acid profile of aerococci was distinguishable from other genera. Two relatively novel fatty acids found in the aerococci were identified as C16:1 omega 9c and C16:1 omega 9t. Eleven strains of aerococci (including a strain originally identified as "Gaffkya" species) were chosen for DNA-DNA reassociation studies with the type strain Aerococcus viridans ATCC 11563; DNAs from eight of these strains were more than 75% related to the type strain and had 1 to 4% divergence in related sequences. The remaining three strains were 60 to 70% related to the type strain, had 7 to 11.5% divergence, and may represent a second species, Aerococcus genospecies 2. beta-Glucuronidase, alpha-galactosidase, and beta-galactosidase were useful in characterizing the aerococci.  相似文献   
76.

Poster Session 3

Multiple sclerosis  相似文献   
77.
78.
OBJECT: The authors sought to establish prospectively whether there is a simple relationship between radiological features of brain arteriovenous malformation (AVM) hemodynamics and a patient's clinical presentation. METHODS: Thirty-one consecutive patients with AVMs underwent cerebral angiography at 3.8 frames/second during each standardized injection of contrast material. Contrast dilution curves were derived from the image sequences by using regions of interest (ROIs) traced on arteries feeding and veins draining the AVM nidus. Angiographic parameters were then analyzed in a blinded fashion. These parameters included the times required to reach the peak contrast density, the contrast decay time, and fractions thereof, in the ROI for each vessel. The authors determined whether these parameters, the arteriovenous transit time, and/or AVM size were related to patients' presentation with hemorrhage (11 patients), seizure (11 patients), or other clinical symptoms (nine patients). Statistically significant results were found only in analyses of arterial phase times to reach peak contrast density. Analyses of venous parameters, AVM size, and nidus transit time showed trends but no statistical significance. Arterial filling with contrast material was significantly slower in patients presenting with hemorrhage (mean 50%, 80%, and 100% of time to peak +/- standard error [SE] = 1.19+/-0.13, 1.97+/-0.18, and 3.04+/-0.34 seconds, respectively) compared with patients presenting with seizures (mean 50%, 80%, and 100% of time to peak +/- SE = 0.80+/-0.12, 1.32+/-0.18, and 1.95+/-0.29 seconds, respectively) according to analysis of variance (p<0.05) and post-hoc t-tests (p<0.05) for each parameter. Patients who presented with other symptoms had intermediate arterial filling times. CONCLUSIONS: These simple hemodynamic parameters, which can be obtained without added risk to the patient, may help identify a subset of individuals in whom AVMs pose a higher risk of future hemorrhage and who may therefore warrant more expeditious treatment.  相似文献   
79.
80.
This study investigates the hypothesis that indomethacin's ability to prevent "fever" following burn injury in rats is mediated via decreased plasma concentrations of IL-6, the putative mediator of increased body temperature. Sprague-Dawley rats had radio transmitters and osmotic pumps containing indomethacin placed in the peritoneal cavity. Seven days later full thickness scald burns to 50% of the body surface area were produced. Following burn injuries, daily blood samples were obtained from a carotid catheter for assay of lipopolysaccharide (LPS), interleukin-1alpha (IL-1alpha), IL-1beta, tumor necrosis factor-alpha (TNF-alpha) and IL-6. In addition, body temperature (T(B)) and activity index were obtained every five minutes by telemetry. There were four experimental groups: burn + indomethacin (B-In); burn + polyethylene glycol (Peg) (B-Peg); control + indomethacin (C-In); and control + Peg (C-Peg). Burned animals demonstrated a significant two-fold increase in plasma IL-1alpha levels (p=0.004) and a seven-fold increment in IL-6 (p=0.0001) through the 7th PBD, and indomethacin administration had no significant effect upon the cytokine plasma levels. There were no significant increases in IL-1beta, TNF-alpha or LPS in any group. Indomethacin eliminated the chronic increase in T(B) following burn injury, and this effect was not produced by changes in plasma levels of the endogenous pyrogens IL-1alpha and IL-6.  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