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   1165篇
  免费   75篇
  国内免费   6篇
耳鼻咽喉   15篇
儿科学   17篇
妇产科学   8篇
基础医学   196篇
口腔科学   34篇
临床医学   65篇
内科学   246篇
皮肤病学   7篇
神经病学   83篇
特种医学   45篇
外科学   206篇
综合类   1篇
预防医学   48篇
眼科学   6篇
药学   104篇
中国医学   6篇
肿瘤学   159篇
  2023年   7篇
  2022年   14篇
  2021年   13篇
  2020年   17篇
  2019年   18篇
  2018年   31篇
  2017年   26篇
  2016年   27篇
  2015年   17篇
  2014年   31篇
  2013年   41篇
  2012年   69篇
  2011年   79篇
  2010年   36篇
  2009年   24篇
  2008年   50篇
  2007年   52篇
  2006年   74篇
  2005年   56篇
  2004年   54篇
  2003年   54篇
  2002年   61篇
  2001年   38篇
  2000年   32篇
  1999年   34篇
  1998年   18篇
  1997年   13篇
  1996年   9篇
  1995年   12篇
  1994年   9篇
  1993年   6篇
  1992年   19篇
  1991年   32篇
  1990年   20篇
  1989年   19篇
  1988年   25篇
  1987年   31篇
  1986年   22篇
  1985年   16篇
  1984年   5篇
  1983年   5篇
  1982年   3篇
  1981年   3篇
  1980年   2篇
  1979年   3篇
  1978年   5篇
  1975年   2篇
  1967年   5篇
  1966年   3篇
  1965年   1篇
排序方式: 共有1246条查询结果,搜索用时 15 毫秒
1.
2.
Rats, initiated to self-administer 10% (v/v) ethanol in an operant situation using the sucrose-fading procedure, received bilateral n. accumbens microinjections of d-amphetamine prior to operant sessions. Doses of 4 micrograms, 10 micrograms and 20 micrograms/brain were administered and some animals also received a 4 microgram/brain dose of LY171555. Three different effects were observed: increased, decreased and no change in total session responding. There was no clear relation between injection area in the n. accumbens and type of effect observed. For either an increase or decrease in total session responding, momentary response rates were decreased. Both d-amphetamine and LY171555 produced similar results. The data support the hypothesis that dopamine in the n. accumbens is involved with ethanol reinforced operant responding but in a complex manner.  相似文献   
3.
An early gastric carcinoma, measuring 1.7 X 0.6 cm, had already metastasized to the extra-perigastric lymph node in a 71 year old symptom-free man. Radiographic and endoscopic studies showed a small depressed lesion on the lesser curvature of the antrum and histology of the biopsied specimen revealed a well differentiated adenocarcinoma. Under the diagnosis of IIc type intramucosal carcinoma, partial gastrectomy and wide lymph node dissection was performed. Pathologic study of the resected specimen showed that the cancer cells had invaded the submucosa at an area via a lymphatic vessel and that only one lymph node along the common hepatic artery was involved.  相似文献   
4.
5.
Innate immunity and its role against infections.   总被引:5,自引:0,他引:5  
LEARNING OBJECTIVES: This article reviews current concepts of the innate immune system that offers protection against infections. It offers an overview for the readers to understand how innate immunity, consisting of different receptors, cells, and mediators recognizes pathogens and exerts protective function against pathogens. DATA SOURCES AND STUDY SELECTION: MEDLINE-search articles including original research papers, review articles, textbooks, and references identified from bibliographies of relevant articles. RESULTS AND CONCLUSIONS: The innate immune system is nonspecific immunity present since birth not requiring repeated exposure to pathogens. It is capable of differentiation between self and nonself. Because of its nonspecificity, it has a broad spectrum of resistance to infection. Further, it is thought to play an important role in the control of adaptive immunity by regulating co-stimulatory molecules and effector cytokines. Innate immunity includes pattern recognition molecules/receptors, antimicrobial peptides, the complement system, inflammatory mediators, and cytokines produced by immune cells. Pattern recognition molecules/receptors recognize pathogen-associated molecular patterns that are essential for microorganisms' survival and pathogenicity. Although innate immunity has recently gained increasing importance, further studies are necessary for a better understanding of its role.  相似文献   
6.
Methyl sulphone metabolites of PCB and DDE were isolated from different tissues of a Baltic grey seal (Halichoerus grypus). Main components in the seal blubber were identified as 3-MeSO2-2,2',4',5,5'-pentaCB, 4-MeSO2-2,2',4',5,5'-pentaCB, 3-MeSO2-p,p'-DDE, 4-MeSO2-2,2',3',4',5-pentaCB and 4-MeSO2-2,2',3,4',5',6-hexaCB. Liver and lung in the seal contained different MeSO2-PCB pattern compared to all other tissues. These levels in the both tissues were estimated to be 28 and 15 ppm (lipid basis) which corresponded to the same level as the PCB. Concentrations of MeSO2-PCB in any tissues of a Yusho patient were low compared to those in the seal.  相似文献   
7.
Long-Evans rats (N = 3) were trained to lever press on a fixed-ratio 4 (FR 4) schedule with ethanol (10% v/v) presented as the reinforcer. Each rat received a total of six bilateral nucleus accumbens microinjections, one per week. They were tested with one physiological saline control, three 20.0-microgram/brain d-amphetamine, and two 6.0-microgram/brain quinpirole injections given 10 min prior to operant sessions. Ethanol-reinforced responding terminated after approximately 10 min during control sessions. Microinjections of the D2 agonist quinpirole and the nonspecific dopamine (DA) agonist d-amphetamine increased total responding but produced slowed response rates that continued for 45-60 min. The slowed response rate produced by d-amphetamine resulted in a peak increase in interresponse times (IRTs) between 8-10 s, whereas quinpirole increased IRTs in the 14- to 16-s range, indicating that nonspecific DA activation resulted in higher rates of ethanol-reinforced responding than specific D2 activation although both drugs decreased local response rates. These data indicate that the amount and temporal extent of ethanol-reinforced responding are increased by microinjections of DA agonists in the nucleus accumbens and support the hypothesis that DA activity in this region is involved in the regulation of ethanol-reinforced responding.  相似文献   
8.
9.
Abstract: The Self-Rating Body Image (SRBI) test was used to determine whether the patients with eating disorders such as anorexia nervosa or bulimia showed their body image disturbance or not. The SRBI was completed by 120 subjects who consisted of 30 low weight (LW) controls, 30 normal weight (NW) controls, 30 high weight (HW) controls, 18 anorexic patients (AN) and 12 bulimic patients (BN). The AN group had a significantly greater dissatisfaction with the scales of the body shape, visceral organ and face image of the SRBI than the weight-matched LW group. The BN group had a significantly greater dissatisfaction with the visceral organ image than the weight-matched NW group. However, no significant difference in the body shape and face images between the BN and NW groups was found. Our results suggest that the anorexic patients may disturb more parts of the body image than the bulimic patients though both the anorexic and bulimic patients showed the disturbance of body image.  相似文献   
10.
Summary The participation of substance P in the noncholinergic contraction induced by transmural stimulation (TMS) of the carp intestinal bulb was examined. In the presence of atropine, substance P caused the contraction of carp intestinal bulb smooth muscle in a concentration dependent manner (1 nmol/1 – 1 mol/l). The EC50 value was 28 ± 7 nmol/l (n = 6). Substance P-induced desensitization (1 mol/l for 15 min), decreased the response to substance P and the atropine-resistant contraction induced by TMS (20 Hz) selectively. In contrast, in the absence of atropine, the contraction induced by TMS (20 Hz) was slightly attenuated with the substance P-induced desensitization. The acid extract obtained from the carp intestinal bulb contained a smooth muscle excitatory material whose pharmacological properties were consistent with those of substance P. The present results indicate that a substance P-like peptide is present in the carp intestinal bulb which is involved in the non-cholinergic contraction induced by TMS.Send offprint requests to T. Kitazawa at the above address  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