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   7292篇
  免费   331篇
  国内免费   18篇
耳鼻咽喉   50篇
儿科学   136篇
妇产科学   244篇
基础医学   1081篇
口腔科学   131篇
临床医学   620篇
内科学   1465篇
皮肤病学   156篇
神经病学   849篇
特种医学   473篇
外国民族医学   1篇
外科学   781篇
综合类   92篇
一般理论   1篇
预防医学   545篇
眼科学   61篇
药学   582篇
  1篇
中国医学   17篇
肿瘤学   355篇
  2021年   104篇
  2020年   52篇
  2019年   89篇
  2018年   99篇
  2017年   87篇
  2016年   105篇
  2015年   160篇
  2014年   212篇
  2013年   235篇
  2012年   341篇
  2011年   347篇
  2010年   215篇
  2009年   208篇
  2008年   291篇
  2007年   309篇
  2006年   296篇
  2005年   310篇
  2004年   268篇
  2003年   270篇
  2002年   299篇
  2001年   222篇
  2000年   237篇
  1999年   226篇
  1998年   88篇
  1997年   71篇
  1996年   53篇
  1995年   74篇
  1994年   70篇
  1992年   94篇
  1991年   77篇
  1990年   96篇
  1989年   125篇
  1988年   120篇
  1987年   96篇
  1986年   114篇
  1985年   131篇
  1984年   75篇
  1983年   69篇
  1981年   59篇
  1979年   86篇
  1978年   65篇
  1977年   68篇
  1976年   54篇
  1975年   56篇
  1973年   75篇
  1972年   61篇
  1971年   77篇
  1970年   59篇
  1969年   59篇
  1968年   51篇
排序方式: 共有7641条查询结果,搜索用时 15 毫秒
91.
Summary The longitudinal muscle-myenteric plexus preparation of the guinea-pig ileum has been employed for the study of the effect of pertussis toxin (IAP) on opioid dependence. Guinea-pigs were treated with IAP (120 g/kg, i.p.) either prior to chronic administration of an opioid or after opioid dependence had been established. The isolated preparations were tested in vitro for dependence; that is, the naloxone-precipitated withdrawal contracture. Naloxone almost failed to evoke a sign of dependence in preparations treated with IAP prior to chronic exposure to an opioid. In contrast, IAP failed to affect the withdrawal contracture when applied to an animal after dependence has been established. It is concluded that theN i-unit, the substrate for IAP, plays a critical function in the development of dependence. The continuous activation of the opioid receptor associated with the development of dependence may induce changes inN i which in turn prevent the interaction of IAP with its substrate.  相似文献   
92.
The endocannabinoid system (ECS) is an endogenous signaling system formed by specific receptors (cannabinoid type 1 and type 2 (CB1 and CB2)), their endogenous ligands (endocannabinoids), and enzymes involved in their synthesis and degradation. The ECS, centrally and peripherally, is involved in various physiological processes, including regulation of energy balance, promotion of metabolic process, food intake, weight gain, promotion of fat accumulation in adipocytes, and regulation of body homeostasis; thus, its overactivity may be related to obesity. In this review, we try to explain the role of the ECS and the impact of genetic factors on endocannabinoid system modulation in the pathogenesis of obesity, which is a global and civilizational problem affecting the entire world population regardless of age. We also emphasize that the search for potential new targets for health assessment, treatment, and the development of possible therapies in obesity is of great importance.  相似文献   
93.
To validate anecdotal evidence on scabies infestations, we analyzed inpatient and outpatient claims data in Germany. Scabies diagnoses increased 9-fold and treatment failure 4-fold during 2009–2018, driven mainly by persons 15–24 years of age. Prevention and control in young adults appear key because of these persons’ high mobility and social connectivity.  相似文献   
94.
We present a heterogeneous non-competitive immunological detection assay for peptide and protein antigens from crude extracts of biological sources. This time-resolved fluoroimmunoassay (TR-FIA) has been designed in a solid-phase mode using 96-well microtiter plates. Using the rare-earth metal europium as a fluorescent marker, a highly sensitive, selective and efficient procedure was developed. This technique prevents from interferences of intrinsic protein fluorescence which is highly important for antigen measurement in complex matrices. The TR-FIA has been applied for the detection of circulating forms of the potential anti-tumor agent endostatin, a C-terminal fragment of collagen XVIII, and its close homolog collagen XV (restin) from hemofiltrate. Endostatin was detected with a limit of detection of 3 ng (150 fmol/well) and a broad dynamic range from 10-1000 ng/well.  相似文献   
95.
96.
Performance priorities for high quality care, multiprofessional team care and deinstitutionalization of patients among mental health services in England and West Germany were found to be significantly influenced by management practices fostering goal congruence, peer review and staff participation in decision making.  相似文献   
97.
Summary -Adrenoceptor-mediated coronary vasoconstriction contributes to the initiation and aggravation of experimental and clinical myocardial ischaemia. However, the extent of 1- and 2-adrenoceptor-mediated constriction has not been characterized in the porcine coronary circulation despite the frequent use of this experimental model.Fifteen swine were anaesthetized with either -chloralose, enflurane or isoflurane to determine the amount of -adrenoceptor-mediated coronary constriction elicited by either the selective 1-adrenoceptor agonist methoxamine or the selective 2-adrenoceptor agonist azepexole. The left anterior descending coronary artery was cannulated and perfused by an external pump delivering constant blood flow from the carotid artery. Following bilateral cervical vagotomy and ß-adrenoceptor blockade with propranolol (2 mg kg–1), graded dosages of either one of the -adrenoceptor agonists (9–45 g kg–1 min–1) were infused into the coronary perfusion line while coronary arterial pressure (CAP) was measured through a distal side arm of the cannula to detect changes in coronary vascular resistance. Infusion of the -adrenoceptor agonists was terminated when systemic arterial pressure increased. Sonomicrometers were used to measure anterior left ventricular wall thickening for the assessment of regional contractile function. During methoxamine infusion, no increase in vascular resistance was observed during -chloralose, enflurane or isoflurane anaesthesia, whereas the infusion of azepexole increased CAP from 103 ± 31 mmHg to 120 ± 35 mmHg (-chloralose), from 101 ± 16 mmHg to 122 ± 11 mmHg (enflurane) and from 84 ± 20 mmHg to 94 ± 19 mmHg (isoflurane), respectively. In four additional swine anaesthetized with enflurane, the intracoronary infusion of the full catecholamine agonist noradrenaline in the presence of propranolol (6 mg kg–1) increased CAP from 98 ± 10 to 105 ± 10 mmHg prior to an increase in regional left ventricular function or systemic arterial pressure.These results indicate that there are no 1- and relatively little 2-adrenoceptor-mediated coronary constrictive effects in swine. Furthermore, neither -adrenoceptor agonist produced any detectable change in regional myocardial contractile function, regardless of the anaesthesia used.Supported by the German Research Foundation (He 1320/3-2). Dr. Guth is the recipient of a scholarship from the Alexander von Humboldt-Foundation. Send offprint requests to G. Heusch at the above address  相似文献   
98.
侧脑室注射血管紧张素Ⅱ促进内源性洋地黄样因子释放   总被引:8,自引:7,他引:1  
目的 探讨侧脑室注射血管紧张素Ⅱ对内源性洋地黄样因子(EDLF)释放的影响。方法 大鼠侧脑室注射血管紧张素Ⅱ及侧脑室注射Saralasin或损毁第三脑室前腹区(AV3V)预处理,放射免疫方法测定血清EDLF浓度的变化。结果 侧脑室注射AngⅡ可引起血清EDLF浓度升高;Saralasin预处理或海人酸损毁AV3V区可阻断侧脑室注射AngⅡ引起的血清EDLF升高效应。结论 侧脑室注射血管紧张素Ⅱ促进EDLF释放。  相似文献   
99.
Baseline data on the perceived health status of participants (N = 5,201) in the Cardiovascular Health Study of the Elderly (CHS) are reported. The authors examined the predictive utility of health-related factors representing eight different domains, assessed gender differences in the prediction of perceived health, and tested a hypothesis regarding the role of known clinical conditions versus subclinical disease in predicting perceived health. Multivariate analyses showed that the majority of the explained variance in self-assessed health is accounted for by variables that fall into four general categories. Although gender differences were small, the analysis showed that the relative importance of several predictor variables did vary by gender.  相似文献   
100.
This article describes the acute and long-term clinical outcomes of 310 consecutive patients who underwent directional coronary atherectomy (DCA) for treatment of coronary artery disease. An overall procedural success rate of 95% was noted with a total major complication rate of 5%. Analyses of minimal luminal diameter (MLD) were performed pre- and post-procedure for 160 patients. Clinical follow-up including treadmill testing and/or clinical symptoms was obtained on 293 patients. Results of angiographic analyses corresponded with the Kuntz model suggesting that larger MLDs are associated with lower restenosis rates. The overall target vessel revascularization rate was 27.6%, with a mean post-procedure percent diameter stenosis of 16%. These results indicate that DCA is associated with acceptable clinical restenosis rates, complications and long-term outcome.  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