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   116041篇
  免费   5910篇
  国内免费   138篇
耳鼻咽喉   1772篇
儿科学   5198篇
妇产科学   3936篇
基础医学   16085篇
口腔科学   2831篇
临床医学   8308篇
内科学   21971篇
皮肤病学   3358篇
神经病学   8978篇
特种医学   5045篇
外国民族医学   32篇
外科学   19017篇
综合类   1595篇
一般理论   29篇
预防医学   5805篇
眼科学   3390篇
药学   8043篇
中国医学   324篇
肿瘤学   6372篇
  2018年   887篇
  2017年   774篇
  2016年   1090篇
  2015年   1218篇
  2014年   1598篇
  2013年   2359篇
  2012年   3092篇
  2011年   3141篇
  2010年   1967篇
  2009年   1927篇
  2008年   3245篇
  2007年   3484篇
  2006年   3627篇
  2005年   3744篇
  2004年   3688篇
  2003年   3553篇
  2002年   3506篇
  2001年   7013篇
  2000年   6959篇
  1999年   5861篇
  1998年   1622篇
  1997年   1559篇
  1996年   1334篇
  1995年   1202篇
  1994年   1094篇
  1993年   1119篇
  1992年   3766篇
  1991年   3578篇
  1990年   3562篇
  1989年   3349篇
  1988年   2986篇
  1987年   2894篇
  1986年   2807篇
  1985年   2619篇
  1984年   1945篇
  1983年   1594篇
  1982年   927篇
  1981年   915篇
  1980年   765篇
  1979年   1823篇
  1978年   1346篇
  1977年   1115篇
  1976年   937篇
  1975年   1179篇
  1974年   1212篇
  1973年   1199篇
  1972年   1040篇
  1971年   975篇
  1970年   880篇
  1969年   787篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The ability of 12 new thiazole derivatives to influence the muscle contractility mediated by purine P2X receptors has been studied in vitro using isolated tissues of rats and guinea pigs. Most of the synthesized compounds did not cause significant effects, but two compounds exhibited pronounced antagonism with respect to P2X-mediated contractility response. These compounds offer a good starting point for the synthesis of new effective antagonists of P2 receptors. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 39, No. 6, pp. 22 – 25, June, 2005.  相似文献   
62.
63.
This prospective study investigated the effects of standard pharmacotherapy in out-of-hospital ventricular fibrillation (VF) after i.v. or endobronchial (e.b.) administration of epinephrine and lidocaine. METHODS. Only patients presenting with out-of-hospital VF were included in this study, whereby VF of noncardiac origin was excluded. Cardiopulmonary resuscitation (CPR) was performed according to the guidelines of the American Heart Association. Basic life support was initiated by Emergency Medical Service (EMS) technicians. The first step of advanced life support was immediate defibrillation by the EMS physician. Epinephrine was given in doses of 2.5 mg e.b. or 1.0 mg i.v. If indicated, patients received 200-500 mg lidocaine e.b. or 100 mg i.v. The course of CPR was tape-recorded and 2-3 blood samples were taken from each patient for drug monitoring. Plasma levels of epinephrine and lidocaine were measured by high-pressure liquid and gas chromatography, respectively, and then correlated to the course of CPR. RESULTS. Forty-seven patients presented VF on arrival of the EMS physician. Restoration of spontaneous circulation was achieved in 64% (Table 3), and 30% of the patients were discharged from hospital without major neurologic deficits. Immediate defibrillation before initiation of pharmacotherapy produced a success rate of 15.8%, whereas defibrillation after drug therapy was successful in 61.5% of cases. Following e.b. instillation of 2.5 mg epinephrine (Fig. 1), median peak concentrations of epinephrine (40.2, range 4.0-79.8 ng/ml) were reached after 3-4 min and plasma levels greater than or equal to 10 ng/ml were seen for 20 min. After i.v. injection of 1.0 mg epinephrine (Fig. 2) maximum concentrations (71.6, range 4.7-104.2 ng/ml) were measured after 1-2 min and plasma levels decreased below 10 ng/ml after 10 min. Following e.b. instillation of 400-500 mg lidocaine mean lidocaine concentrations within the therapeutic range (2-5 micrograms/ml) were reached after 4-5 min and remained within these limits for 20-30 min. Peak concentrations were obtained after 12 min. Doses of 200-320 mg lidocaine e.b. failed to achieve therapeutic plasma levels (Fig. 3). Regarding the pharmacodynamic aspects of drug therapy, 22.5% of the initial survivors were resuscitated from VF without therapeutic epinephrine, presenting with mean endogenous epinephrine concentrations of 7.1 ng/ml, 51.6% of patients were resuscitated after epinephrine therapy with plasma concentrations greater than 20 ng/ml. In only 1 case could a relationship be demonstrated between the administration of lidocaine and resuscitation success. CONCLUSION. In CPR, the e.b. administration of epinephrine and lidocaine is a reliable alternative to the i.v. injection route of these drugs. Recommended doses are 2.5 mg for epinephrine and 400-500 mg for lidocaine. Resuscitation from VF requires immediate epinephrine therapy if initial defibrillation is not successful. Lidocaine has no effect on resuscitation from VF and therefore should be used specifically for antiarrhythmic therapy after restoration of spontaneous circulation.  相似文献   
64.
Thirty patients with progressive metastatic breast cancer and one prior chemotherapy regimen were treated with iproplatin at a starting dose of 300 mg/m2 iv every 3 weeks. After the first 11 patients, the starting dose was decreased to 270 mg/m2. There were one complete remission, three partial remissions, and two minor responses. Responses were observed in soft tissue and osseous and visceral areas. Grade 3 nausea and vomiting were observed in 38% of patients, and grade 3 diarrhea occurred in 31%. The dose-limiting toxicity was thrombocytopenia, which required dose de-escalation in 15 patients. No nephrotoxicity, neurotoxicity, or ototoxicity was observed. Iproplatin has modest antitumor activity in this group of previously treated patients with metastatic breast cancer.  相似文献   
65.
66.
Two young men with longstanding suprapatellar masses are presented. The initial clinical diagnosis was of a synovial or soft tissue tumour. Magnetic resonance imaging showed the features of an arteriovenous malformation (AVM). Surgical exploration and biopsy confirmed the diagnosis. AVMs, although rare, should be considered as a possible diagnosis of a peri-articular swelling of the knee.  相似文献   
67.
We investigated the effects of anti-psoriatic therapy with dithranol (1/20-1%) in salicylic acid (0.5%) in white petrolatum on lesional skin. FITC-labeled lectins and pemphigus vulgaris antibodies (PV) served as analytical means to study the glycocalyx. Antibodies of bullous pemphigoid (BP) were used as basal membrane markers. Nuclear antigens were recorded according to the binding of speckled, anti-nuclear antibodies (ANA) as well as antibodies to dsDNA. With some lectins, dithranol therapy resulted in pronounced fluorescence of the lower parts of the basal cells. ConA was fixed by the basal cell layer. To a lesser degree, ANA were fixed by nuclei of keratinocytes. PV antibodies were not fixed at all.  相似文献   
68.
69.
70.
BACKGROUND AND AIMS: Liver surgery is developing with new techniques and treatment modalities. The aim of this study is to describe liver surgery over a long period of time in a country with a public health care system. PATIENTS AND METHOD: A register study including adult patients admitted for liver resection in Sweden (population 8.8 million) selected from the Inpatient Register 1987-99. Additional data were collected from the Swedish Cancer Register and the Cause of Death Register. Analyses of the patients, indications, mortality and causes of death are presented. RESULTS: 2,405 operations were performed (21 per million per year). The most frequent indication was colorectal metastases (27%). The 5-year survival after an operation for primary liver cancer and colorectal liver metastases was 27% and 26%, respectively. CONCLUSIONS: Few patients were admitted for liver operations compared to expected figures. The survival rates are in conformity with those previously published. With an increasing awareness of the relatively favourable prognosis and the introduction of new methods, the volume of liver operations will probably increase in Sweden.  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