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   3880篇
  免费   252篇
  国内免费   10篇
耳鼻咽喉   35篇
儿科学   88篇
妇产科学   81篇
基础医学   455篇
口腔科学   39篇
临床医学   468篇
内科学   579篇
皮肤病学   48篇
神经病学   430篇
特种医学   133篇
外科学   627篇
综合类   44篇
一般理论   2篇
预防医学   358篇
眼科学   122篇
药学   285篇
  1篇
肿瘤学   347篇
  2023年   18篇
  2022年   56篇
  2021年   108篇
  2020年   60篇
  2019年   111篇
  2018年   132篇
  2017年   91篇
  2016年   90篇
  2015年   90篇
  2014年   134篇
  2013年   227篇
  2012年   278篇
  2011年   308篇
  2010年   181篇
  2009年   160篇
  2008年   243篇
  2007年   231篇
  2006年   224篇
  2005年   197篇
  2004年   189篇
  2003年   185篇
  2002年   152篇
  2001年   48篇
  2000年   48篇
  1999年   42篇
  1998年   25篇
  1997年   19篇
  1996年   19篇
  1995年   24篇
  1994年   32篇
  1993年   16篇
  1992年   38篇
  1991年   30篇
  1990年   33篇
  1989年   36篇
  1988年   20篇
  1987年   20篇
  1986年   18篇
  1985年   15篇
  1984年   20篇
  1983年   18篇
  1982年   11篇
  1980年   7篇
  1979年   21篇
  1978年   10篇
  1977年   17篇
  1975年   8篇
  1974年   11篇
  1973年   9篇
  1969年   11篇
排序方式: 共有4142条查询结果,搜索用时 15 毫秒
91.
Patients with polycythemia vera and essential thrombocythemia are at risk for thrombotic and bleeding complications. Currently, no diagnostic test can predict thrombohemorrhagic complications. In a prospective study of 86 patients with polycythemia vera (43 patients) or essential thrombocythemia (43 patients), we examined the possible role of polymorphisms of platelet adhesion receptors [glycoprotein (GP) Ibalpha, GPIa, GPIIIa) and clotting factor II (prothrombin's G20210A mutation) and clotting factor V (Leiden mutation) in determining the risk of thrombotic or bleeding complications. Except for an association between vasomotor symptoms and prothrombin mutation (P < 0.001), no significant correlation between polymorphism of clotting factors and thrombohemorrhagic complications was identified. When the entire patient cohort was considered, the polymorphisms of platelet adhesion receptors were not associated with the risk for thrombotic or bleeding complications. However, among patients with polycythemia vera, the presence of the PlA2 allele of GPIIIa was associated with an increased risk of arterial thrombosis. In view of previous studies linking the presence of the PlA2 allele of GPIIIa to a higher risk for coronary artery thrombosis, our data have physiologic relevance. However, they need to be confirmed in a larger study.  相似文献   
92.
We report a case of a woman with recurrent axillary fungating breast cancer who developed catastrophic hemorrhage from tumor erosion of her axillary artery. This was treated successfully with endovascular placement of a covered arterial stent. We discuss the suitability of endovascular therapy for patients with advanced malignancy given its lower morbidity in this population with decreased life expectancy.  相似文献   
93.
94.
95.
96.
OBJECTIVE: Intrauterine growth restriction (IUGR) is characterized by decreased placental perfusion. Low oxygen has been shown to increase soluble fms-like tyrosine kinase 1 (sFlt-1) expression in the human placenta. The objective of this study was to examine sFlt-1 expression in different types of IUGR pregnancies, including early-onset severe cases characterized by abnormal umbilical and uterine artery Doppler and discordant IUGR twins in which the normal cotwin represents the optimal control because both placentas share the same uterine environment. PATIENTS: Placentas from four subgroups were collected: early severe IUGR with umbilical artery absent end diastolic flow (n = 19), small for gestational age with normal uterine and umbilical artery Doppler (n = 11), severely growth-restricted dichorionic and monochorionic twins with abnormal umbilical artery Doppler (n = 9), preeclamptic twins (n = 3), and age-matched normal singletons (n = 19) and twin controls (n = 8). RESULTS: Expression of sFlt-1 mRNA and protein was significantly increased in IUGR placentas compared with small for gestational age and normal control placentas. sFlt-1 expression levels were also significantly greater in the small IUGR twin placentas from discordant twin pregnancies compared with the normal cotwin. In preeclamptic twins, sFlt-1 expression was increased in only one of the two placentas. CONCLUSIONS: Our results demonstrate that sFlt-1 expression is increased in severe IUGR placentas with abnormal umbilical artery Doppler of singletons and also in discordant IUGR twins. Reduced placental perfusion may contribute to the increased expression of sFlt-1 in IUGR pregnancies. Our data are compatible with differential sFlt-1 expression in placentas from discordant twins.  相似文献   
97.
Erectile Impotence in Chronic Alcoholics   总被引:1,自引:0,他引:1  
Erectile impotence is a common complaint in alcoholics, but its mechanism is unknown. We have studied nocturnal penile erection in 13 alcoholics who complained of impotence. Seven had normal erections and their impotence was therefore psychogenic. Six were found to have diminished or absent nocturnal erections. Plasma concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were elevated in this latter group, with the exception of one patient who had only raised FSH. They also had more evidence of neurological damage than the other seven alcoholics, and two had evidence of damage to the parasympathetic nervous system. Investigation of erection during sleep in alcoholic patients with impotence may be useful in differentiating clinically between patients with psychogenic causes and patients with organic causes of impotence.  相似文献   
98.
99.
100.
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