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   8877篇
  免费   718篇
  国内免费   66篇
耳鼻咽喉   63篇
儿科学   311篇
妇产科学   304篇
基础医学   1160篇
口腔科学   278篇
临床医学   850篇
内科学   1817篇
皮肤病学   72篇
神经病学   537篇
特种医学   343篇
外科学   1478篇
综合类   170篇
一般理论   10篇
预防医学   422篇
眼科学   340篇
药学   502篇
中国医学   31篇
肿瘤学   973篇
  2024年   9篇
  2023年   58篇
  2022年   74篇
  2021年   215篇
  2020年   144篇
  2019年   192篇
  2018年   250篇
  2017年   134篇
  2016年   190篇
  2015年   244篇
  2014年   334篇
  2013年   348篇
  2012年   547篇
  2011年   622篇
  2010年   392篇
  2009年   363篇
  2008年   546篇
  2007年   596篇
  2006年   568篇
  2005年   512篇
  2004年   456篇
  2003年   410篇
  2002年   312篇
  2001年   303篇
  2000年   259篇
  1999年   208篇
  1998年   79篇
  1997年   75篇
  1996年   69篇
  1995年   54篇
  1994年   54篇
  1993年   47篇
  1992年   112篇
  1991年   99篇
  1990年   100篇
  1989年   102篇
  1988年   71篇
  1987年   72篇
  1986年   66篇
  1985年   60篇
  1984年   43篇
  1983年   38篇
  1982年   32篇
  1981年   32篇
  1980年   28篇
  1979年   24篇
  1978年   18篇
  1977年   26篇
  1976年   17篇
  1975年   15篇
排序方式: 共有9661条查询结果,搜索用时 15 毫秒
991.
This study examined the incidence of PTSD and psychiatric co-morbidity among women who experienced stillbirth and investigated the relationship between locus of control, trauma characteristics of stillbirth, posttraumatic cognitions, PTSD and co-morbid psychiatric symptoms following stillbirth. Fifty women recorded information on stillbirth experiences, and completed the Posttraumatic Stress Diagnostic Scale, General Health Questionnaire-28, Edinburgh Post-natal Depression Scale, Rotter’s Locus of Control Scale and the Posttraumatic Cognitions Inventory. 60, 28 and 12 % met the diagnostic criteria for probable full-PTSD, partial and no-PTSD respectively. Sixty-two percent and 54 % scored at or above the cutoff of the General Health Questionnaire-28 and postnatal depression respectively. Women who experienced stillbirth reported significantly more psychiatric co-morbid and post-natal depressive symptoms than the comparison group. Both groups were similar in locus of control. Women who experienced stillbirth reported negative cognitions about the self the most. After adjusting for postnatal depression, trauma characteristics were significantly correlated with Posttraumatic cognitions which, in turn, were significantly correlated with PTSD and psychiatric co-morbidity. Locus of control was not significantly correlated with psychological outcomes. Mediational analyses showed that negative cognitions about self mediated the relationship between trauma characteristics and psychiatric co-morbidity only. Women reported a high incidence of probable PTSD and co-morbid psychiatric symptoms following stillbirth. Stillbirth trauma characteristics influenced how they negatively perceived themselves. This then specifically influenced general psychological problems rather than PTSD symptoms.  相似文献   
992.
993.
994.
M C Tsang  A C Lo  P T Cheung  S S Chung  S K Chung 《Neuroreport》2001,12(10):2265-2270
Under pathological conditions in the adult CNS, such as ischemia, subarachnoid hemorrhage and Alzheimer's disease, endothelin (ET)-1- and -3-like immunoreactivities are elevated in astrocytes of the injured adult brain. However, it is not clear whether this is due to increased synthesis or increased binding of ET-1. Further, it is not known whether ET-1 expression is altered in the perinatal brain after cerebral hypoxia/ischemia (H/I). Here, we determined the sites of ET-1 expression in perinatal mouse brain after H/I injury by in situ hybridization using a probe specific for the ET-1 gene. Astrocyte-like cells, which do not normally express ET-1 mRNA, showed high levels of ET-1 mRNA expression. Endothelial cells of the capillaries and small vessels also showed an increased level of ET-1 mRNA. Our data suggest that ET-1 mRNA levels in the astrocyte-like cells and vascular endothelial cells are dynamically regulated by ischemia and may participate in perinatal ischemia-related neural damage.  相似文献   
995.
Cell-based approaches are a promising therapeutic strategy for treating injuries to the nervous system, but the optimal means to promote neurite extension and direct cellular behavior are unclear. Previous studies have examined the behavior of neural-like cells in ambient air (21% oxygen tension), yet these conditions are not representative of the physiological oxygen microenvironment of neural tissues. We hypothesized that neuronal differentiation of a model neural cell line (PC12) could be controlled by modulating local oxygen tension. Compared to ambient conditions, PC12 cells cultured in reduced oxygen exhibited significant increases in neurite extension and total neurite length, with 4% oxygen yielding the highest levels of both indicators. We confirmed neurite extension was mediated through oxygen-responsive mechanisms using small molecules that promote or inhibit HIF-1α stabilization. The hypoxic target gene Vegf was implicated as a neurotrophic factor, as neurite formation at 21% oxygen was mimicked with exogenous VEGF, and a VEGF-neutralizing antibody attenuated neurite formation under reduced oxygen conditions. These findings demonstrate that behavior of neural-like cells is driven by the oxygen microenvironment via VEGF function, and suggest promising approaches for future applications in neural repair.  相似文献   
996.
997.
This study aimed to determine whether retinal fractal dimension, a quantitative measure of microvascular branching complexity and density, is associated with lacunar stroke. A total of 392 patients presenting with acute ischemic stroke had retinal fractal dimension measured from digital photographs, and lacunar infarct ascertained from brain imaging. After adjusting for age, gender, and vascular risk factors, higher retinal fractal dimension (highest vs lowest quartile and per standard deviation increase) was independently and positively associated with lacunar stroke (odds ratio [OR], 4.27; 95% confidence interval [CI], 1.49–12.17 and OR, 1.85; 95% CI, 1.20–2.84, respectively). Increased retinal microvascular complexity and density is associated with lacunar stroke. ANN NEUROL 2010;68:107–111  相似文献   
998.
999.
1000.
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