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   14272篇
  免费   1062篇
  国内免费   27篇
耳鼻咽喉   165篇
儿科学   361篇
妇产科学   241篇
基础医学   2140篇
口腔科学   414篇
临床医学   1678篇
内科学   2608篇
皮肤病学   177篇
神经病学   1308篇
特种医学   457篇
外科学   1488篇
综合类   241篇
一般理论   32篇
预防医学   1516篇
眼科学   428篇
药学   1024篇
中国医学   17篇
肿瘤学   1066篇
  2022年   81篇
  2021年   144篇
  2020年   123篇
  2019年   211篇
  2018年   211篇
  2017年   178篇
  2016年   213篇
  2015年   247篇
  2014年   301篇
  2013年   589篇
  2012年   757篇
  2011年   889篇
  2010年   578篇
  2009年   488篇
  2008年   783篇
  2007年   849篇
  2006年   882篇
  2005年   865篇
  2004年   888篇
  2003年   819篇
  2002年   883篇
  2001年   372篇
  2000年   361篇
  1999年   276篇
  1998年   214篇
  1997年   171篇
  1996年   144篇
  1995年   160篇
  1994年   134篇
  1993年   133篇
  1992年   154篇
  1991年   154篇
  1990年   127篇
  1989年   130篇
  1988年   105篇
  1987年   97篇
  1986年   98篇
  1985年   111篇
  1984年   95篇
  1983年   108篇
  1982年   120篇
  1981年   132篇
  1980年   111篇
  1979年   98篇
  1978年   67篇
  1977年   66篇
  1976年   67篇
  1975年   62篇
  1974年   67篇
  1973年   52篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
Chromosome analysis has been widely used as a first step in eclucidating the genetic architecture of several behaviors ofDrosophila melanogaster. These chromosome studies have generally used incomplete designs or fairly simple statistical analyses. Here I reanalyze two data sets on geotaxis from Pyle (1978) and Ksander (1966) using a biometrical genetic design. Results from the biometrical genetic reanalysis suggest that individual differences in geotaxis might be due to genes on all three major chromosomes which show extensive epistatic interactions.  相似文献   
43.
Diagnosis of fetal rubella infection by nucleic acid hybridization   总被引:4,自引:0,他引:4  
The efficacy of nucleic acid hybridization for the diagnosis of rubella infection in experimental and clinical materials was compared with immunoblot and virus isolation techniques. Our results showed that nucleic acid hybridization is specific and rapid but gives false-negative results when compared with conventional virus isolation in some experimental although not in clinical materials so far examined. For this reason, a failure to demonstrate rubella virus in fetal specimens by this method alone cannot yet be taken as a sole criterion for ruling out fetal rubella infection.  相似文献   
44.
The influence of cefodizime (CDZ) on CD4 and CD8 lymphocytes was investigated in patients with lower respiratory tract infection and underlying respiratory diseases. Ten men and one woman were treated with CDZ 1 g i.m. b.i.d. for ten days. The infecting organisms wereHaemophilus influenzae (5),Streptococcus pneumoniae (2) andEscherichia coli (1). No adverse events were reported. Nine patients were clinically cured; two required further antibiotic therapy. Leucocyte counts decreased significantly during treatment. Lymphocyte counts and CD4 cells both increased significantly in absolute and relative numbers, while there was a much smaller increase in CD8 cells. This resulted in a significant increase in the CD4/CD8 ratio. These effects of CDZ might be of benefit for immunocompromised patients with bacterial infections.Der Einfluß von Cefodizim (CDZ) auf CD4 und CD8 Lymphozyten wurde bei Patienten mit Infektionen der tiefen Atemwege und chronischen Grundkrankheiten der Atemwege untersucht. Zehn Männer und eine Frau wurden über zehn Tage mit 2×1 g CDZ i.m. behandelt. Folgende Keime wurden isoliert:Haemophilus influenzae 5×,Streptococcus pneumoniae 2× undEscherichia coli 1x. Unerwünschte Arzneiwirkungen wurden nicht beobachtet. Klinische Heilung trat bei neun Patienten ein, zwei benötigten weiterhin antibiotische Behandlung. Im Lauf der Behandlung kam es zu einer signifikanten Abnahme der Leukozyten. Dagegen wurde bei Lymphozyten und CD4 Zellen ein signifikanter Anstieg beobachtet. Während bei CD8 Zellen nur eine geringe, statistisch nicht signifikante Erhöhung eintrat, stieg der CD4/CD8 Quotient signifikant an. Diese Wirkungen von CDZ könnten sich für Patienten mit bakteriellen Infekten und Störungen der Immunabwehr günstig auswirken.  相似文献   
45.
Whereas water loss in land living animals occurs continuously, water intake takes place discontinuously. At the normal operating set point of plasma osmolality, urine is more concentrated than plasma due to secretion of vasopressin. Thus animals operate around a state of mild dehydration. As water loss occurs, the severity of dehydration and thirst increase in intensity and at some point water intake occurs. Sufficient water is consumed to return plasma osmolality to the normal operating set point. Food intake and water balance are interdependent as food provides the osmoles which determine obligatory renal solute excretion. When dry food with the same osmotic content was substituted for canned food (water content 74%), dogs increased water intake from 24.2 +/- 4.3 to 62.2 +/- 8.8 ml/kg. Urine output and urine osmolality were unchanged, as under conditions of normal hydration, near maximal urine concentration is achieved. Changing water intake is the only available variable to maintain water balance. During water deprivation, the major renal mechanism appears to be natriuresis. In rehydration, satiety mechanisms ensure appropriate water intake and renal sodium conservation restores sodium balance.  相似文献   
46.
47.
48.
Introduction:  Occupational contact dermatitis (OCD) is very common in the printing industry due to contact with chemicals, paper, and wet work. It can be avoided by adequate protective measures, but the effectiveness of intervention depends heavily on the employer's and employee's awareness of this health risk.
Objectives:  The study aimed to collect information on the knowledge, attitudes and beliefs of print workers about the risk of OCD and methods of prevention.
Methods:  A series of focus groups were held with print workers, health and safety officers and managers to discuss their awareness of dermal risk factors, risk behaviour at work, attitudes to health and safety and options on possible preventive measures. A number of companies were also visited to observe, overtly and covertly, the normal work practices.
Results:  OCD was not perceived to be either a major problem or a health and safety priority. There was general agreement about the processes and work practices that could cause skin problems. However, work practices varied considerably and did not always reflect this awareness. There was general concern about the type and availability of personal protective equipment, especially gloves and after‐work skin cream. The provision of an occupational health service was generally felt to be inadequate, and no company had a policy in place that specifically addressed skin care.
Conclusions:  These findings highlight the urgency to intensify health and safety education on skin care within the printing industry. Recommendations were developed for the evaluation of a series of risk reduction strategies.  相似文献   
49.
50.
This case report describes a dog suffering from a co‐infection with Babesia and Anaplasma parasites. Anaplasma platys was found to be responsible for the anaplasmosis by molecular biology techniques, while microscopical and serological evidence was found for a coexistent babesiosis, although this could not be confirmed by polymerase chain reaction. Moreover, the possible risk of import of exotic pathogens is highlighted.  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