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   22564篇
  免费   1324篇
  国内免费   139篇
耳鼻咽喉   163篇
儿科学   371篇
妇产科学   215篇
基础医学   2717篇
口腔科学   533篇
临床医学   1454篇
内科学   5544篇
皮肤病学   1411篇
神经病学   1903篇
特种医学   983篇
外科学   3804篇
综合类   111篇
一般理论   1篇
预防医学   560篇
眼科学   213篇
药学   1843篇
中国医学   44篇
肿瘤学   2157篇
  2023年   162篇
  2022年   130篇
  2021年   660篇
  2020年   338篇
  2019年   454篇
  2018年   583篇
  2017年   490篇
  2016年   585篇
  2015年   568篇
  2014年   729篇
  2013年   767篇
  2012年   1276篇
  2011年   1312篇
  2010年   702篇
  2009年   577篇
  2008年   1084篇
  2007年   1180篇
  2006年   1083篇
  2005年   1033篇
  2004年   993篇
  2003年   911篇
  2002年   817篇
  2001年   607篇
  2000年   665篇
  1999年   631篇
  1998年   261篇
  1997年   177篇
  1996年   163篇
  1995年   152篇
  1994年   126篇
  1993年   111篇
  1992年   445篇
  1991年   395篇
  1990年   401篇
  1989年   423篇
  1988年   399篇
  1987年   368篇
  1986年   319篇
  1985年   287篇
  1984年   171篇
  1983年   152篇
  1982年   80篇
  1979年   164篇
  1978年   81篇
  1977年   84篇
  1974年   71篇
  1973年   83篇
  1972年   83篇
  1970年   74篇
  1969年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
BACKGROUND: We are developing an immunotherapeutic peptide, Cry-consensus peptide, for Japanese cedar pollinosis. Cry-consensus peptide is a recombinant polypeptide containing six major human T-cell epitopes derived from both Cry j 1 and Cry j 2, two major allergens of Japanese cedar pollen. We examined the effect of Cry-consensus peptide on an allergic rhinitis model in B10.S mice, which have one common T-cell epitope in the Cry-consensus peptide. METHODS: B10.S mice were sensitized with Cry j 1/alum, then the Cry-consensus peptide was administered subcutaneously once a week for 5 weeks from the last sensitization. Histamine was dropped in both nostrils (10 microL per nostril) of each mouse on the day before continuous intranasal instillation of Cry j 1. Soon after the final challenge with Cry j 1, the mice were observed for 5 minutes for the resulting number of sneezes. In addition, serum levels of Cry j 1-specific IgE and IgG2a antibody, eosinophil infiltration in nasal tissue, and Cry j 1-specific cytokine production from splenocytes were evaluated. RESULTS: Cry-consensus peptide markedly inhibited Cry j 1-induced sneezes, eosinophil infiltration, and eosinophil peroxidase (EPO) activity in nasal tissue. Cry-consensus peptide inhibited the production of anti-Cry j 1 IgE (Th2-mediated) and significantly enhanced anti-Cry j 1 IgG2a (Th1-mediated). In cytokine production from splenocytes, Cry-consensus peptide significantly decreased in IL-4/IFN-gamma and IL-5/IFN-gamma ratios. CONCLUSIONS: It was concluded that Cry-consensus peptide effectively controlled allergic responses, which results from shifting from a Th2-dominated to a Th1-dominated immune response.  相似文献   
93.
94.
Acute ligation of proximal left coronary artery was performed on forty male Sprague-Dawley rats. Five min later, occlusion was released in order to evaluate the effectiveness of the 3 antiarrhythmic drugs in eliminating reperfusion ventricular arrhythmias. The drugs evaluated were moricizine (5 mg/kg), disopyramide (DSP) (5 mg/kg) and mexiletine (MXT) (5 mg/kg), which were administered intravenously 5 min before ligation of the coronary artery. Compared to control rats that underwent identical experimental procedures, all 3 drugs significantly lowered the mortality rate from 90% of the control group to 20, 20 and 0% for moricizine, DSP and MXT groups. The incidence of ventricular fibrillation (Vf) was also decreased significantly by these drugs. The duration of ventricular tachycardia (VT) and Vf of surviving rats in drug groups were 111.7 +/- 35.0 sec, 71.6 +/- 29.4 sec and 32.9 +/- 14.6 sec for moricizine, DSP and MXT, respectively. Many of the drug treated rats could be restored to the normal sinus rhythm and survived. All 3 drugs slowed the heart rate significantly, but as for the blood pressure only MXT showed significant suppressing effect. In conclusion, moricizine has the same significant preventive effect on reperfusion induced ventricular tachyarrhythmias as DSP and MXT.  相似文献   
95.
To evaluate the clinical significance of scintigraphic overlap of thallium-201 (201T1) and technetium-99m pyrophosphate (99mTc), we observed 28 patients with acute myocardial infarction (AMI) in whom coronary reperfusion was attempted. All patients underwent dual energy emission computed tomography (D-ECT) on the third post AMI day which facilitated comparing 99mTc and 201T1 images from identical slices simultaneously. The scintigraphic results of the 28 patients were as follows: (table, see text) In conclusion, (1) significant 201T1 and 99mTc overlap on D-ECT suggest very early and successful reperfusion, and (2) none of the patients with unsuccessful reperfusion exhibits overlap.  相似文献   
96.
Zusammenfassung Es erfolgte eine retrospektive mikromorphologische Analyse der Glandula parotis und/oder der Glandula submandibularis von 180 plötzlichen Kindstodesfällen in Berlin und 75 Fällen in Hamburg. Erfaßt wurden Fälle der letzten 10 Jahre mit einem Alter zwischen 2 Wochen und einem Lebensjahr. — Typische CMV-Einschlußkörper wurden im Berliner Material in 18 Fällen (10%; Mädchen mehr als Jungen) und im Hamburger Material in 6 Fällen (7%; Jungen mehr als Mädchen) diagnostiziert. Während die meisten SIDS-Fälle sich im zweiten und dritten Lebensmonat ereigneten, war bei den CMV-Infektionen kein Altersgipfel festzustellen. Virusmaterial war mit immunhistochemischen Unterschungen sowie in-situ-Hybridisierung auch in histologisch unauffälligen Zellen nachzuweisen. — Unter Berücksichtigung der bekannten klinischen und epidemiologischen Daten zur Cytomegalie stellt die Diagnose einer lokalisierten Infektion der Kopf-speicheldrüsen keine befriedigende Erklärung für den plötzlichen Tod der Säuglinge dar; diese Befunde sind jedoch besonders beachtenswert als Hinweis auf eine Schwäche des Immunsystems.  相似文献   
97.
98.
Prostaglandin E1 (PGE1) has several potential therapeutic effects, including cytoprotection, vasodilation, and inhibition of platelet aggregation. This study investigates the protective action of PGE1 against hepatic ischemia/reperfusion injury in vivo using a complementary DNA microarray. PGE1 or saline was continuously administered intravenously to mice in which the left lobe of the liver was made ischemic for 30 minutes and then reperfused. Livers were harvested 0, 10, and 30 minutes postreperfusion. Messenger RNA was extracted, and the samples were labeled with two different fluorescent dyes and hybridized to the RIKEN set of 18,816 full-length enriched mouse complementary DNA microarrays. Serum alanine aminotransferase and aspartate aminotransferase levels at 180 minutes postreperfusion were significantly lower in the PGE1-treated group than in the saline-treated group. The cDNA microarray analysis revealed that the genes encoding heat-shock protein (HSP) 70, glucose-regulated protein 78, HSP86, and glutathione S-transferase were upregulated at the end of the ischemic period (0 minutes postreperfusion) in the PGE1 group. Our results suggested that PGE1 induces HSPs immediately after ischemia reperfusion. HSPs might therefore play an important role in the protective effects of PGE1 against ischemia/reperfusion injury of the liver.  相似文献   
99.
We presented here two patients with hemorrhagic infarction occurred during subacute phase of brain embolism. The patients were 71-year-old and 73-year-old men who suffered from brain infarction of the left posterior cerebral artery and right middle cerebral artery territory, respectively. Both of them were diagnosed as having cryptogenic stroke and patent foramen ovale. After transferred to rehabilitation hospitals taking aspirin for a secondary prevention of stroke, they developed hemorrhagic infarction at day 17 and day 19, respectively. Their blood pressure remained within normal range throughout acute and subacute phase. Although most of hemorrhagic infarction occurs within 24 hours of stroke onset, some patients develop symptomatic hemorrhagic infarction even after 10 days. We need to be careful about late-onset hemorrhagic infarction, because many patients are now transferred early to rehabilitation hospitals to facilitate dedicated systematic rehabilitation.  相似文献   
100.
Purpose: We examined muscle strength and walking ability after hernia repair to compare the effects of laparoscopic hernioplasty and conventional repair. Methods: Twenty-seven patients with primary inguinal hernias were randomly divided into two groups according to the surgical procedure: 15 patients were treated with laparoscopic hernioplasty and 12 with conventional repair. Two types of muscle testing around the inguinal region, one by manual examination and one using a musculator, were done preoperatively and 1 week postoperatively. Walking exercise tests were performed at the same time as muscle testing. Results: Manual examination showed that the postoperative muscle strength of the iliopsoas muscle was decreased in six patients from the conventional repair group, but not in any of those from the laparoscopic hernioplasty group. The musculator showed decreased strength of the iliopsoas muscle after conventional repair, but not after laparoscopic hernioplasty. The walking exercise test showed that conventional hernia repair influenced walking. Conclusion: A decline in muscle strength of the iliopsoas muscle and walking ability was evident after conventional repair, but not after laparoscopic hernioplasty. Thus, laparoscopic hernioplasty is superior to conventional repair from the perspective of muscle testing and walking ability. Received: March 29, 2002 / Accepted: July 2, 2002 Reprint requests to: N. Murata  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