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   4701篇
  免费   351篇
  国内免费   10篇
耳鼻咽喉   39篇
儿科学   77篇
妇产科学   124篇
基础医学   591篇
口腔科学   32篇
临床医学   611篇
内科学   906篇
皮肤病学   41篇
神经病学   481篇
特种医学   166篇
外科学   669篇
综合类   120篇
一般理论   7篇
预防医学   401篇
眼科学   109篇
药学   383篇
中国医学   9篇
肿瘤学   296篇
  2023年   22篇
  2022年   37篇
  2021年   62篇
  2020年   50篇
  2019年   78篇
  2018年   107篇
  2017年   74篇
  2016年   103篇
  2015年   121篇
  2014年   147篇
  2013年   207篇
  2012年   340篇
  2011年   358篇
  2010年   198篇
  2009年   166篇
  2008年   295篇
  2007年   340篇
  2006年   316篇
  2005年   325篇
  2004年   323篇
  2003年   269篇
  2002年   243篇
  2001年   60篇
  2000年   60篇
  1999年   60篇
  1998年   55篇
  1997年   47篇
  1996年   39篇
  1995年   38篇
  1994年   33篇
  1993年   37篇
  1992年   35篇
  1991年   34篇
  1990年   30篇
  1989年   31篇
  1988年   27篇
  1987年   29篇
  1986年   21篇
  1985年   28篇
  1984年   22篇
  1983年   15篇
  1982年   19篇
  1981年   12篇
  1980年   14篇
  1979年   20篇
  1977年   13篇
  1976年   10篇
  1975年   9篇
  1974年   12篇
  1973年   8篇
排序方式: 共有5062条查询结果,搜索用时 15 毫秒
21.
Over a 12 year period, 25 psoas abscesses occurring in 17 patients were managed at Royal Perth Hospital (900 bed hospital). Symptoms were present, on average, for 5 weeks prior to diagnosis, which was typically confirmed by computerized tomography. Fifty-nine per cent of cases were primary and percutaneous drainage effected a cure in 80% of all cases. Percutaneous drainage resulted in a non-significant trend towards shorter inpatient stay.  相似文献   
22.
Cyclic nucleotides are important second messengers that mediate a number of cellular responses to external signals. Cyclic nucleotide phosphodiesterases play a role in signal transduction by regulating the cellular concentrations of these messengers. Here, we have applied Southern analyses of somatic cell hybrid lines and of recombinant inbred (RI) mouse strains as well as fluorescence chromosomal in situ hybridization (FISH) to chromosomally localize five cAMP-specific nucleotide phosphodiesterase genes in human and mouse. GenesDPDE1, DPDE2, DPDE3, andDPDE4 that share sequence homology with theDrosophila dunce gene were assigned to human chromosomes 19 (DPDE1 andDPDE2), 5q12 (DPDE3), and 1p31 (DPDE4) and to mouse chromosomes 8, 9, 13, and 4, respectively. The high-affinity cAMP-specific phosphodiesterase gene (HCP1) was mapped to human chromosome 8q13-q22. Since these genes are potential candidates for involvement in psychiatric or behavioral disorders, knowledge of their chromosomal localizations will facilitate the discovery of their association with disease genes as they are being mapped by linkage studies.  相似文献   
23.
The effects of gemfibrozil on several indices of haemostatic activity were explored in male patients with coronary heart disease (CHD). Sixty-three of 71 patients completed a crossover study in which gemfibrozil 1,200 mg/day and matching placebo were each taken in randomised order for 2 months in a double-blind manner, separated by a 2-month washout period. Serum cholesterol decreased by an average (95% confidence interval) of 12 (9 to 15)% and non-fasting triglyceride concentration by 43 (34 to 51)% during active treatment. Plasma prothrombin fragment F1 + 2 concentration, a marker of the in vivo rate of generation of thrombin, was 25 (12 to 37)% lower on average while on gemfibrozil than during the placebo phase. Factor VII coagulant activity (VIIc) and antigen concentration, and fibrinopeptide A concentration were not influenced by gemfibrozil in the group overall. However, the VIIc response appeared to be dependent upon the untreated cholesterol level. Hypercholesterolaemic men (cholesterol greater than 6.5 mmol/l) experienced a significant reduction in VIIc averaging 6% of standard during active therapy. Other effects of gemfibrozil were a 5 (2 to 9)% increase in plasma fibrinogen by a gravimetric method, an 11 (8 to 13)% increase in platelet count, and a 6 (2 to 10)% reduction in white cell count. The reduced incidence of CHD following gemfibrozil therapy in hyperlipidaemic patients may arise in part through a reduction in procoagulant activity and thus the risk of an occlusive coronary thrombosis.  相似文献   
24.
Eleven mammalian toll-like receptors (TLRs 1–11) have been identified to date and are known to play a crucial role in the regulation of immune responses; however, the factors that regulate TLR expression and function in vivo are poorly understood. Therefore, in the present study, we investigated the physiological regulation of TLR expression and function in humans. To examine the influence of diurnal rhythmicity on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers ( n = 8) at time points coinciding with the peak and nadir in the endogenous circulating cortisol concentration. While no diurnal rhythmicity in the expression of TLRs 1, 2, 4 or 9 was observed, the upregulation of costimulatory (CD80 and CD86) and antigen-presenting (MHC class II) molecules on CD14+ monocytes following activation with specific TLR ligands was greater ( P < 0.05) in samples obtained in the evening compared with the morning. To examine the influence of physical stress on TLR expression and function, peripheral venous blood samples were collected from healthy volunteers ( n = 11) at rest and following 1.5 h of strenuous exercise in the heat (34°C). Strenuous exercise resulted in a decrease ( P < 0.005) in the expression of TLRs 1, 2 and 4 on CD14+ monocytes. Furthermore, the upregulation of CD80, CD86, MHC class II and interleukin-6 by CD14+ monocytes following activation with specific TLR ligands was decreased ( P < 0.05) in samples obtained following exercise compared with at rest. These results demonstrate that TLR function is subject to modulation under physiological conditions in vivo and provide evidence for the role of immunomodulatory hormones in the regulation of TLR function.  相似文献   
25.
26.
To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case.  相似文献   
27.
28.
29.
Trauma is the third most common cause of death in the West. In the US, approximately 90,000 deaths annually are traumatic in nature and over 75% of casualties from blunt trauma are due to chest injuries. Cardiac injuries from rib fractures following blunt trauma are extremely rare. We report the unusual case of a patient who fell from a height and presented with haemopericardium and haemothorax as a result of left ventricular and lingular lacerations and was sucessfully operated upon.  相似文献   
30.
This is the third edition of this popular book on anaestheticequipment. It is primarily intended for trainees in anaesthesia,but will also be very useful to nurses working in anaesthesiaand intensive care and operating department practitioners. Thebook is split into the same 14 chapters as the second edition.Two new appendices covering sterilization and cleaning of medicalequipment and latex  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