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   1441087篇
  免费   107614篇
  国内免费   2217篇
耳鼻咽喉   18302篇
儿科学   45639篇
妇产科学   38677篇
基础医学   211952篇
口腔科学   38612篇
临床医学   134922篇
内科学   284630篇
皮肤病学   29648篇
神经病学   119186篇
特种医学   52636篇
外国民族医学   278篇
外科学   206320篇
综合类   28742篇
现状与发展   5篇
一般理论   849篇
预防医学   121157篇
眼科学   31838篇
药学   104826篇
  8篇
中国医学   2358篇
肿瘤学   80333篇
  2021年   12268篇
  2019年   12777篇
  2018年   16883篇
  2017年   13102篇
  2016年   14188篇
  2015年   16418篇
  2014年   23023篇
  2013年   35002篇
  2012年   48437篇
  2011年   51919篇
  2010年   29910篇
  2009年   28384篇
  2008年   49087篇
  2007年   52430篇
  2006年   51710篇
  2005年   51191篇
  2004年   49216篇
  2003年   46847篇
  2002年   45362篇
  2001年   57647篇
  2000年   58280篇
  1999年   49821篇
  1998年   15760篇
  1997年   14320篇
  1996年   14555篇
  1995年   13608篇
  1994年   12623篇
  1993年   11817篇
  1992年   39246篇
  1991年   38679篇
  1990年   37338篇
  1989年   36084篇
  1988年   33549篇
  1987年   32911篇
  1986年   31376篇
  1985年   29705篇
  1984年   23216篇
  1983年   20433篇
  1982年   12909篇
  1979年   21638篇
  1978年   16209篇
  1977年   13588篇
  1976年   12547篇
  1975年   13401篇
  1974年   16168篇
  1973年   15869篇
  1972年   14883篇
  1971年   13855篇
  1970年   13081篇
  1969年   12280篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A child was brought for evaluation of signs of unilateral chronic progressive sciatic nerve dysfunction found to be due to nerve entrapment in the thigh by a fibrovascular band. Sectioning of the band was followed by marked improvement in the nerve function. Compression by a band is a rare but treatable cause of sciatic neuropathy.  相似文献   
992.
This study compared the results of reflex modification (RM)--an objective technique for assessing brainstem sensorineural processing--with those of auditory brainstem response (ABR) for a group of high-risk infants at comparable postconceptional ages. For the RM procedure, an eyeblink-eliciting tap to the glabella was presented either alone or accompanied by a brief 90dB SPL tone. 37 high-risk infants were tested with both RM and ABR at a mean postconceptional age of 37.3 weeks. Seven had an increased brainstem conduction time ('failed ABR') and eight did not exhibit significant reflex augmentation ('failed RM'), seven of whom also failed the ABR. These data provide evidence that sensory stimuli which affect the neural mechanisms responsible for the organization of the startle response and auditory processing share essential neural components.  相似文献   
993.
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   
994.
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   
995.
996.
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   
997.
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   
998.
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   
999.
1000.
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   
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