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   23098篇
  免费   652篇
  国内免费   85篇
耳鼻咽喉   360篇
儿科学   704篇
妇产科学   1019篇
基础医学   1553篇
口腔科学   258篇
临床医学   922篇
内科学   7295篇
皮肤病学   409篇
神经病学   2320篇
特种医学   538篇
外科学   3678篇
综合类   450篇
一般理论   1篇
预防医学   1581篇
眼科学   546篇
药学   1237篇
  1篇
中国医学   113篇
肿瘤学   850篇
  2023年   437篇
  2022年   1130篇
  2021年   1094篇
  2020年   925篇
  2019年   2667篇
  2018年   2904篇
  2017年   956篇
  2016年   348篇
  2015年   374篇
  2014年   1545篇
  2013年   1241篇
  2012年   959篇
  2011年   1188篇
  2010年   939篇
  2009年   714篇
  2008年   723篇
  2007年   751篇
  2006年   572篇
  2005年   512篇
  2004年   375篇
  2003年   278篇
  2002年   232篇
  2001年   138篇
  2000年   101篇
  1999年   127篇
  1998年   104篇
  1997年   108篇
  1996年   88篇
  1995年   74篇
  1994年   75篇
  1993年   101篇
  1992年   55篇
  1991年   68篇
  1989年   59篇
  1988年   70篇
  1987年   62篇
  1986年   57篇
  1985年   182篇
  1984年   227篇
  1983年   180篇
  1982年   164篇
  1981年   175篇
  1980年   128篇
  1979年   108篇
  1978年   89篇
  1977年   72篇
  1976年   76篇
  1975年   69篇
  1974年   75篇
  1973年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study was aimed to investigate the reproductive health in adult male rats exposed to di‐n‐butyl phthalate (DBP) during embryonic development. Pregnant rats were injected with DBP and F1 male rats were weaned and on postnatal day 100, used for mating with normal cycling females to assess reproductive performance. After completion of cohabitation period, rats were analyzed for other reproductive end points. Transplacental exposure to DBP significantly decreased fertility in adult male rats. Prenatal exposure to DBP significantly decreased sperm density, number of motile sperms, viable sperms, and hypoosmotic swelling tail coiled sperms with an increase in morphological abnormalities in sperms. Testicular steroidogenic enzyme activity levels and serum testosterone levels were significantly decreased in rats exposed to DBP during embryonic development. In conclusion, transplacental exposure to DBP impairs male reproductive performance by decreasing steroidogenesis and spermatogenesis. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 534–544, 2014.  相似文献   
992.
The aim of this study was to investigate the effects of quercetin and fish n‐3 fatty acids on the changes in testis induced by ethanol. Forty‐five rats divided into five groups, control, ethanol, ethanol+quercetin, ethanol+fish n‐3 fatty acids and ethanol+quercetin+fish n‐3 fatty acids. At the end of 8 weeks, all the rats were sacrificed. Degenerative changes in histopathological analyses, the decreased body weight gain and seminiferous tubule diameters in ethanol group have been observed. TUNEL assay also showed an increase in apoptotic cell number. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH‐Px), xanthine oxidase (XO) and testosterone levels were decreased as well as the levels of malondialdehyde (MDA) and nitric oxide (NO) were increased in ethanol group. Histopathological changes caused by ethanol have been improved by quercetin and fish n‐3 fatty acids. It was also found that protection was provided by increasing SOD, CAT and GSH‐Px activities in groups administered quercetin, fish n‐3 fatty acids and quercetin+fish n‐3 fatty acids, and by decreasing the levels of MDA and NO in groups administered both quercetin and fish n‐3 fatty acids together. These results suggest that quercetin and fish n‐3 fatty acids are beneficial agents to reduce testicular injury induced by ethanol except for testosterone levels.  相似文献   
993.
Lower limbs superficial venous thrombosis (LLSVT) is usually considered as common and of a benign prognosis. LLSVT can, however, be responsible for major thromboembolic complications: lower limbs deep vein thrombosis (LLDVT) and pulmonary embolism (PE). We report a case of a LLSVT complicated with a massive bilateral PE and an ischemic cerebral stroke, occurring immediately after a varicose vein surgery. Venous ultrasonography of the lower limbs must be systematically performed in case of LLSVT, in order to evaluate the presence of an associated LLDVT. A rigorous diagnostic and therapeutic approach is the only way to optimize the treatment of this disorder, and to avoid the occurrence of dramatic venous thromboembolic complications.  相似文献   
994.
995.
996.
Since 2005, forgoing live-support (FLS) is allowed by the French law (known as the Leonetti law) for end-of-life patients only. This study aims at describing the variations over time in the use of the following methods to end life: FLS, brain death and cardiopulmonary resuscitation failure (CPR failure). It is a single retrospective study from 2007 to 2012. The Cochran-Armitage trend test is used in the statistical analysis. Over six years, 263 of the 5100 children who were hospitalized in our intensive care unit died, which represents a 5.2% mortality rate. FLS increased yearly from 31% of the deaths in 2007, to 71% in 2012 (P = 0.0008). The rate of CPR failure decreased over the same period (P = 0.0015). The rate of brain death remained constant. Following to the Leonetti law, FLS increase, and palliative cares develop without any increase of mortality.  相似文献   
997.
Lymphohistiocytic activation syndrome (LHAS) is related to inappropriate stimulation of macrophage cells in bone marrow and lymphoid system. LHAS combines the non-specific clinical signs (fever, poor general condition, hepatosplenomegaly, lymphadenopathy) and suggestive biological elements (bi-or pancytopenia, abnormal liver function, coagulopathy, increased LDH, ferritin and triglycerides). The diagnosis of SALH remains an emergency every clinician should discuss before any febrile cytopenia. The etiology of LHAS is still obscure, but recent advances in the genetic study of familial forms provide some essential elements in understanding.  相似文献   
998.
999.
We report the anesthetic management with total intravenous anesthesia of a 61-year-old male diagnosed with limb-girdle muscular dystrophy admitted for replacement of ascending aorta due to an aortic aneurysm. Limb-girdle muscular dystrophy belongs to a genetically heterogeneous group of muscular dystrophies involving shoulder and hip girdles. Although the risk of malignant hyperthermia does not seem to be increased in these patients compared with the general population, the exposure to inhaled anesthetics and succinylcholine should probably be avoided because these patients have a predisposition to hyperkalemia and rhabdomyolysis. We chose to use total intravenous anesthesia with propofol, remifentanil and muscle relaxants to reduce oxygen consumption, and later to reduce the doses of propofol and remifentanil. The combination of a carefully planned anesthetic strategy, anesthetic depth, and neuromuscular blockade monitoring is explained.  相似文献   
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