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   10374篇
  免费   561篇
  国内免费   23篇
耳鼻咽喉   80篇
儿科学   305篇
妇产科学   284篇
基础医学   1815篇
口腔科学   211篇
临床医学   999篇
内科学   1850篇
皮肤病学   169篇
神经病学   1093篇
特种医学   471篇
外科学   1255篇
综合类   88篇
一般理论   3篇
预防医学   887篇
眼科学   131篇
药学   686篇
中国医学   29篇
肿瘤学   602篇
  2022年   54篇
  2021年   143篇
  2020年   92篇
  2019年   128篇
  2018年   157篇
  2017年   122篇
  2016年   159篇
  2015年   209篇
  2014年   268篇
  2013年   379篇
  2012年   639篇
  2011年   677篇
  2010年   392篇
  2009年   357篇
  2008年   603篇
  2007年   631篇
  2006年   614篇
  2005年   635篇
  2004年   577篇
  2003年   513篇
  2002年   530篇
  2001年   98篇
  2000年   60篇
  1999年   94篇
  1998年   128篇
  1997年   92篇
  1996年   81篇
  1995年   86篇
  1994年   68篇
  1993年   62篇
  1992年   46篇
  1991年   65篇
  1990年   48篇
  1989年   51篇
  1985年   47篇
  1984年   53篇
  1983年   43篇
  1982年   45篇
  1981年   40篇
  1974年   44篇
  1933年   71篇
  1932年   59篇
  1931年   57篇
  1930年   52篇
  1929年   44篇
  1928年   45篇
  1927年   52篇
  1926年   54篇
  1925年   49篇
  1924年   52篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
131.
Crude extracts of 57 species of European fungi have been tested for their bactericidal (Bacillus subtilis, Escherichia coli), fungicidal (Candida albicans, Cladosporium cucumerinum), larvicidal (Aedes aegypti), molluscicidal (Biomphalaria glabrata), antioxidant and free-radical scavenging activities. Connatine and 2(3,4-dihydroxyphenyl)glycine, two compounds with antioxidant and free-radical scavenging properties, were subsequently isolated from the methanolic extracts of Lyophyllum connatum (Tricholomataceae) and Cortinarius hercynicus (Cortinariaceae), respectively. In addition, linoleic acid was shown to be molluscicidal.  相似文献   
132.
Severe and recurrent purpura fulminans developed in a Turkish boy at 1 week of age. Initial coagulation studies performed were compatible with disseminated intravascular coagulation. Subsequent investigations showed that the patient had homozygous and his healthy parents had heterozygous protein C deficiency. The episodes of purpura fulminans were controlled by infusions of fresh frozen plasma and heparinization. Oral anticoagulant therapy was given in the symptom-free period.  相似文献   
133.
The aims of the study were to investigate healthy subjects’ performance on a clinical test of high-level language (HLL) and how it is related to demographic characteristics and verbal working memory (VWM). One hundred healthy subjects (20–79 years old) were assessed with the Swedish BeSS test (Laakso, Brunnegård, Hartelius, & Ahlsén, 2000) and two digit span tasks. Relationships between the demographic variables, VWM and BeSS were investigated both with bivariate correlations and multiple regression analysis. The results present the norms for BeSS. The correlations and multiple regression analysis show that demographic variables had limited influence on test performance. Measures of VWM were moderately related to total BeSS score and weakly to moderately correlated with five of the seven subtests. To conclude, education has an influence on the test as a whole but measures of VWM stood out as the most robust predictor of HLL.  相似文献   
134.
Filamentous fungi cultured from respiratory tract specimens submitted to the department of clinical microbiology, Aarhus University Hospital, during 2010 were identified by morphology and by internal transcribed spacer (ITS) sequencing. Of 343 fungal isolates, discrepancies between identification methods were observed for four isolates (1.2%), while identification to species was achieved only with ITS sequencing for 16 isolates (4.7%). Filamentous fungi were isolated from 15% of cystic fibrosis (CF) respiratory samples in contrast to 2% of non‐CF samples. From CF patients, a total of nine different species were found in 188 samples from 48 patients, whereas from non‐CF patients, 24 different species were found in 155 samples from 111 patients. CF was associated with a significant overrepresentation of Aspergillus fumigatus and Scedosporium species; in contrast, the frequency of Penicillium spp. and other putative contaminants were significantly increased in non‐CF patients. The altered species variation of filamentous fungi in CF respiratory specimens is contradictory to a scenario of incidentally inhaled spores, trapped in the viscous airway mucus of these patients and subsequently expectorated; rather, our data most likely reflect both an increased prevalence and an increased proportion of truly colonizing fungi in this patient group.  相似文献   
135.
136.
137.
Aims: The aim of this study is to investigate the effect of mitral stenosis (MS) on left atrial (LA) function using two‐dimensional speckle tracking echocardiography (2DSTE). Methods and Results: The study subjects consisted of 52 patients with asymptomatic MS and 52 control subjects. LA function was assessed using prototype speckle tracking software and manual tracking method. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) and LA volume before atrial contraction (LAVpre‐a) were measured. Using these volumes, LA reservoir, conduit and booster pump fuction parameters were calculated. Indexed LAVmax, LAVmin, and LAVpre‐a measurements via speckle tracking were highly correlated with manual tracing methods in both groups. Expansion index (67.8 ± 36.4 vs. 148.3 ± 44.2), diastolic emptying index (37.7 ± 12.9 vs. 58.0 ± 8.5), passive emptying (37.3 ± 14.1 vs. 70.4 ± 10.4) and passive emptying index (13.3 ± 6.3 vs. 41.3 ± 10.6) were decreased significantly in MS patients (P < 0.001). In contrast active emptying index (62.6 ± 4.1 vs. 29.5 ± 10.1) increased in MS group (P < 0.001) while active emptying (28.1 ± 13.0 vs. 28.3 ± 6.9) remained same among both groups. Conclusions: This is the first study relating LA volumes and function assessed by 2DSTE to MS. 2D speckle tracking analysis of LA volume is relatively easy and provides more detailed information regarding the changes in LA volumes during the cardiac cycle.  相似文献   
138.
139.
140.
ObjectiveThe purpose of this study was to investigate the relationship between 12 work-related stressors and the occurrence of adverse events in an emergency department (ED).MethodsNurses and physicians, working in an ED at a Danish regional hospital, filled out a questionnaire on occurrence and emotional impact of 12 work-related stressors after each shift during a 4-week period. The questionnaire also instructed the participants to describe any adverse events that they were involved in during the shift.ResultsTwo hundred fourteen adverse events were reported during the 979 studied shifts. During the same period, only 27 adverse events were reported to the mandatory national reporting system, and only 10 of these were duplicates. A high variability of stressors and emotional impact among the different groups of participants was found. Linear regression analysis showed an association between involvement in adverse events and the occurrence and emotional impact of stressors across groups, whereas no significant association was found for age, seniority, shift type, or length.ConclusionThe study showed an association between the occurrence and impact of 12 work-related stressors and involvement in adverse events across the groups of participants. Furthermore, the study showed that most adverse events were not reported to the mandatory national reporting system.  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