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   1328249篇
  免费   96064篇
  国内免费   2112篇
耳鼻咽喉   18879篇
儿科学   43699篇
妇产科学   39154篇
基础医学   195260篇
口腔科学   36746篇
临床医学   113147篇
内科学   261606篇
皮肤病学   27242篇
神经病学   104055篇
特种医学   52120篇
外国民族医学   404篇
外科学   204239篇
综合类   26956篇
现状与发展   1篇
一般理论   368篇
预防医学   96780篇
眼科学   29990篇
药学   101361篇
  1篇
中国医学   2638篇
肿瘤学   71779篇
  2018年   12785篇
  2016年   10854篇
  2015年   12556篇
  2014年   17142篇
  2013年   26350篇
  2012年   36073篇
  2011年   38592篇
  2010年   23069篇
  2009年   21584篇
  2008年   37333篇
  2007年   40408篇
  2006年   40932篇
  2005年   40110篇
  2004年   38717篇
  2003年   37466篇
  2002年   37080篇
  2001年   59593篇
  2000年   61129篇
  1999年   52103篇
  1998年   14923篇
  1997年   13382篇
  1996年   13581篇
  1995年   12868篇
  1994年   12183篇
  1993年   11311篇
  1992年   42007篇
  1991年   41362篇
  1990年   40847篇
  1989年   39692篇
  1988年   36929篇
  1987年   36204篇
  1986年   34509篇
  1985年   32870篇
  1984年   24479篇
  1983年   21318篇
  1982年   12735篇
  1981年   11271篇
  1979年   23113篇
  1978年   16153篇
  1977年   13991篇
  1976年   13193篇
  1975年   14501篇
  1974年   17010篇
  1973年   16352篇
  1972年   15594篇
  1971年   14472篇
  1970年   13423篇
  1969年   12903篇
  1968年   12112篇
  1967年   10628篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Women with pre-eclampsia have an increased risk of cardiovascular disease later in life. The aim of the study was to establish the presence and pattern of arterial stiffness in women previously with pre-eclampsia from a semi-rural region of South Africa. This was a prospective longitudinal study which involved 36 previously pre-eclamptic women and 86 non-pregnant controls (NPC) who had a past history of non-complicated pregnancy. Maternal wave reflection (augmentation index) and carotid-femoral pulse wave velocity were assessed noninvasively, using applanation tonometry with the SphygmoCor device. Endothelial function was assessed by EndoPAT 2000 device; pneumatic probes were fitted to the index fingers; induced flow-mediated reactive hyperemia; the ratio of the readings before and after occlusion was then used to calculate the score, the reactive hyperemia index (RHI) as a measure of endothelial function.

Pulse wave velocity remained significantly higher in previously pre-eclamptic women than non-pregnant controls up to three months after delivery (p < 0.05), then it reduced to nonsignificant values. All blood pressure indices (central and brachial pressures), were higher in previously pre-eclamptic women as compared to nonpregnant controls up to one year postpartum.

Regional (aortic) arterial stiffness, though it persists for some time after delivery, is transitory in previously pre-eclamptic women from the rural Africa setting. However, their increase blood pressure is an indication of compromised arterial compliance in women previously with pre-eclampsia.  相似文献   

82.
83.
84.
85.
86.
87.
88.
Theory: Immersive simulation is a common mode of education for medical students. Observation of clinical simulations prior to participation is believed to be beneficial, though this is often a passive process. Active observation may be more beneficial. Hypotheses: The hypothesis tested in this study was that the active use of a simple checklist during observation of an immersive simulation would result in better participant performance in a subsequent scenario compared with passive observation alone. Methods: Medical students were randomized to either passive or active (with checklist) observation of an immersive simulation involving cardiac arrest prior to participating in their own simulation. Performance measures included time to cardiopulmonary resuscitation (CPR) and time to defibrillation and were compared between first and second scenarios as well as between passive and active observers. Results: Seventy-nine simulations involving 232 students were conducted. Mean time to CPR was 18 seconds (SD = 11.6) for those using the checklist and 24 seconds (SD = 15.8) for those who observed passively (M difference = 6 seconds), t(35) = 1.46, p =.153. Time to defibrillation was 94 seconds (SD = 26.4) for those using the checklist and 92 seconds (SD = 23.8) for those who observed passively (M difference = –2 seconds), t(38) =.21, p =.837. Time to CPR was 24 seconds (SD = 15.8) for passive observers and 31 seconds (SD = 21.0; M difference = 7 seconds), t(35) = 1.13, p =.265, for their first scenario counterparts. Time to CPR was 18 seconds (SD = 11.6) for active observers and 36 seconds (SD = 26.2; M difference = 18 seconds), t(24) = 2.81, p =.010, for their first scenario counterparts. Time to defibrillation was 92 seconds (SD = 23.8) for passive observers and 125 seconds (SD = 32.2; M difference = 33 seconds), t(33) = 3.63, p =.001, for their first scenario counterparts. Time to defibrillation was 94 seconds (SD = 26.4) for the active observers and 132 seconds (SD = 52.9; M difference = 38 seconds), t(28) =.46, p =.008, for their first scenario counterparts. Conclusions: Observation alone leads to improved performance in the management of a simulated cardiac arrest. The active use of a simple skills-based checklist during observation did not appear to improve performance over passive observation alone.  相似文献   
89.
The normal function of the hypothalamic-pituitary-adrenal (HPA) axis, and resultant glucocorticoid (GC) secretion, is essential for human health. Disruption of GC regulation is associated with pathologic, psychological, and physiological disease states such as depression, post-traumatic stress disorder, hypertension, diabetes, and osteopenia, among others. As such, understanding the mechanisms by which HPA output is tightly regulated in its responses to environmental stressors and circadian cues has been an active area of investigation for decades. Over the last 20 years, however, advances in gene targeting and genome modification in rodent models have allowed the detailed dissection of roles for key molecular mediators and brain regions responsible for this control in vivo to emerge. Here, we summarize work done to elucidate the function of critical neuropeptide systems, GC-signaling targets, and inflammation-associated pathways in HPA axis regulation and behavior, and highlight areas for future investigation.  相似文献   
90.
HIV risk in vulnerable groups such as itinerant male street labourers is often examined via a focus on individual determinants. This study provides a test of a modified Information-Motivation-Behavioral Skills (IMB) model to predict condom use behaviour among male street workers in urban Vietnam. In a cross-sectional survey using a social mapping technique, 450 male street labourers from 13 districts of Hanoi, Vietnam were recruited and interviewed. Collected data were first examined for completeness; structural equation modelling was then employed to test the model fit. Condoms were used inconsistently by many of these men, and usage varied in relation to a number of factors. A modified IMB model had a better fit than the original IMB model in predicting condom use behaviour. This modified model accounted for 49% of the variance, versus 10% by the original version. In the modified model, the influence of psychosocial factors was moderately high, whilst the influence of HIV prevention information, motivation and perceived behavioural skills was moderately low, explaining in part the limited level of condom use behaviour. This study provides insights into social factors that should be taken into account in public health planning to promote safer sexual behaviour among Asian male street labourers.  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