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   1283737篇
  免费   96302篇
  国内免费   1619篇
耳鼻咽喉   16548篇
儿科学   41666篇
妇产科学   35431篇
基础医学   192024篇
口腔科学   35318篇
临床医学   120210篇
内科学   251039篇
皮肤病学   27570篇
神经病学   103724篇
特种医学   47398篇
外国民族医学   266篇
外科学   181938篇
综合类   26146篇
现状与发展   3篇
一般理论   581篇
预防医学   106631篇
眼科学   28549篇
药学   93614篇
  7篇
中国医学   2027篇
肿瘤学   70968篇
  2018年   13926篇
  2017年   10678篇
  2016年   11584篇
  2015年   13387篇
  2014年   18531篇
  2013年   28242篇
  2012年   38601篇
  2011年   41079篇
  2010年   23717篇
  2009年   22807篇
  2008年   38693篇
  2007年   41417篇
  2006年   40952篇
  2005年   40152篇
  2004年   38515篇
  2003年   36867篇
  2002年   35720篇
  2001年   56458篇
  2000年   57468篇
  1999年   48503篇
  1998年   13656篇
  1997年   12406篇
  1996年   12833篇
  1995年   12072篇
  1994年   11286篇
  1993年   10553篇
  1992年   38554篇
  1991年   37968篇
  1990年   36724篇
  1989年   35534篇
  1988年   32968篇
  1987年   32267篇
  1986年   30775篇
  1985年   29041篇
  1984年   22138篇
  1983年   19397篇
  1982年   11519篇
  1981年   10491篇
  1979年   21175篇
  1978年   15567篇
  1977年   12928篇
  1976年   11978篇
  1975年   12945篇
  1974年   15752篇
  1973年   15526篇
  1972年   14646篇
  1971年   13687篇
  1970年   12896篇
  1969年   12155篇
  1968年   11298篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
991.
Reproductive Function in Epilepsy   总被引:10,自引:10,他引:0  
Summary: : The hypothalamic-pituitary-gonadal axis is a complex system within which both positive and negative feedback occur among its elements and higher brain systems. The occurrence of seizures and changes in the secretion of pituitary hormones can affect the feedback loop. Both seizures and antiepileptic drugs can affect the hypothalamic-pituitary-gonadal axis of males and females and cause changes in hormones and sexuality. Reproductive dysfunction has a social impact because of reduced fertility. Once conception occurs, live birth rates are not diminished. Prospective studies of men and women with epilepsy are needed.  相似文献   
992.
M Balázs  G Vadász  I Koncz  E Simon 《Orvosi hetilap》1991,132(39):2143-2146
15 patients with congestive gastropathy were reported including clinical and pathological characteristics of the disease. Every patient had alcoholic liver cirrhosis and portal hypertension. 6 patient's stomach was resected while in 2 further cases the disease was found at autopsy. In additional 7 cases the characteristic microvascular changes were observed in endoscopic biopsy specimens from the gastric mucosa. The authors presume that this disease has an acute and a chronic stage. In the acute stage dilated capillaries are present under the surface, not related to the inflammation of gastric mucosa. This phenomenon was described in the literature. In the chronic stage there are dilated and tortuous vessels in the submucosal layer surrounded by collagenous connective tissue. The authors suppose that the thick and fibrotic submucosal layer causes microcirculatory disturbances in the gastric mucosa. The impaired microcirculation may cause extensive ulcers with profuse and sometimes lethal bleeding.  相似文献   
993.
994.
Operative mortality, postoperative morbidity and follow up data were analyzed retrospectively from 122 consecutive patients, over 65 years old undergoing elective aortocoronary bypass grafting for symptomatic relief of angina pectoris at the Plains Health Centre, Regina, Saskatchewan, from January 1980 to December 1985. There were two in-hospital deaths (operative mortality 1.6%). Definite perioperative myocardial infarction occurred in 12 patients (9.8%). The 120 survivors were followed for a mean of 32 months. There were three deaths during follow-up, giving a five-year probability of survival of 93%. Twenty-three clinical events (including deaths) occurred during follow-up, giving a five-year probability of event free survival of 72%. Ninety percent of patients say they are pleased with their operation. Seventy-eight percent are currently angina free. These data illustrate the effectiveness of aortocoronary bypass grafting in low risk elderly patients with symptomatic coronary artery disease.  相似文献   
995.
The emergence of a near-haploid clone of cells in blast phase chronic myelogenous leukemia is an unusual event. We report such a case and review eight other cases described in the English literature. The significance of the substantial loss of genetic material is discussed as is the phenotypic and genotypic heterogeneity observed in this group of patients.  相似文献   
996.
We evaluated the isoform composition of heavy and light chains of myosin in single muscle fibers from patients with Duchenne dystrophy, myotonic dystrophy, or polymyositis. In all myopathic muscles, there was an increase in the proportion of intermediate fibers which, by analysis of myosin isoforms, fell into two subpopulations, one that contained both fast and slow myosin and another that contained myosin molecular hybrids. The increased proportion of intermediate (or transitional) fibers suggests changes in the equilibrium between fast and slow motor units. These changes could result from regeneration and subsequent maturation of fibers or from direct transformation of mature fibers of one type into the opposite.  相似文献   
997.
998.
Renal vascular reactivity in jaundice   总被引:1,自引:0,他引:1  
Obstructive jaundice is associated with a predisposition to hypotension and acute renal failure that may be related to changes in renovascular responsiveness, particularly to norepinephrine (NE). This study was undertaken to investigate changes in vascular response to NE and to determine how these changes are related to prostaglandins. Kidneys from bile duct-ligated (BDL) rabbits (n = 5) were perfused with Krebs' solution at 7.65 ml/min, and the response to varying boluses of NE (0.78 to 6.24 micrograms) was measured as changes in perfusion pressure. When compared with sham-operated control kidneys (n = 8), a significantly blunted response was seen at all doses tested. The NE response was further assessed by measuring force development in mounted segments of main renal arteries (MRAs) (n = 8) and interlobar arteries (ILAs) (n = 6) from BDL rabbits and sham-operated controls (MRA, n = 8; ILA, n = 6). The dose-response curves were significantly depressed in both MRAs and ILAs from BDL animals. In addition, MRAs from sham-operated control animals exhibited decreased response to NE after incubation for 1 hour in jaundiced serum. This attenuated response of MRAs to NE was prevented when indomethacin (5 mg/kg) was given to BDL rabbits before death (n = 9) or when 10(-6)mol/L of indomethacin was added to jaundiced serum during incubation (n = 6). These results indicate that obstructive jaundice induces a decreased vascular contractile response in rabbits to NE and that this effect is mediated by prostaglandins.  相似文献   
999.
1000.
Studies of former prisoners of war (POWs) provide valuable insights into posttraumatic adaptation because they gather information from a large population who survived the traumatic experiences of military captivity. Previous studies of POWs have shown elevated rates of psychiatric symptoms and disorders. This report presents evidence from a longitudinal study of three large, representative, national samples of former POWs. The study finds that depressive symptomatology, as measured by the Center for Epidemiologic Studies Depression Scale, is elevated in World War II POWs from the Pacific and European theaters and in Korean conflict POWs. Decades later, depressive symptomatology is found to be strongly associated with prior treatment in captivity. Differences in depressive symptomatology among the three POW groups can be attributed to captivity-related factors and to buffering factors, such as age at capture and education.  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