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   3002篇
  免费   44篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   68篇
妇产科学   72篇
基础医学   377篇
口腔科学   68篇
临床医学   446篇
内科学   358篇
皮肤病学   30篇
神经病学   140篇
特种医学   128篇
外科学   319篇
综合类   39篇
预防医学   228篇
眼科学   75篇
药学   530篇
中国医学   55篇
肿瘤学   118篇
  2023年   71篇
  2022年   63篇
  2021年   98篇
  2020年   133篇
  2019年   116篇
  2018年   96篇
  2017年   75篇
  2016年   131篇
  2015年   122篇
  2014年   204篇
  2013年   125篇
  2012年   84篇
  2011年   64篇
  2010年   154篇
  2009年   147篇
  2008年   34篇
  2007年   78篇
  2006年   80篇
  2005年   80篇
  2004年   90篇
  2003年   86篇
  2002年   107篇
  2001年   97篇
  2000年   54篇
  1999年   90篇
  1998年   76篇
  1997年   80篇
  1996年   95篇
  1995年   66篇
  1994年   46篇
  1993年   28篇
  1992年   32篇
  1991年   34篇
  1990年   29篇
  1989年   18篇
  1988年   64篇
  1987年   5篇
排序方式: 共有3052条查询结果,搜索用时 421 毫秒
31.
Clinical trial outcome reporting differs between studies integrating traditional Chinese medicine (TCM) and Western medicine, so that some clinical trials are not eligible for inclusion in a systematic review. The excluded studies are therefore less widely disseminated, and even valid studies are less likely to yield impact. This problem may be addressed by developing core outcome sets (COSs) for integrative medicine in specific healthcare areas. The first stage of development is to define the scope of the COS for integrative medicine, the second stage is to establish the need for such a COS, and the third stage is to develop a protocol and register the COS. The final stage involves three steps: (i) development of a comprehensive list of outcomes (including efficacy outcomes and safety outcomes and TCM syndromes) using systematic review, qualitative or cross-sectional research, and reviews of package inserts and medical records; (ii) merging and grouping of outcomes within domains; (iii) conducting two rounds of Delphi survey and consensus meetings with a range of stakeholders. The final COS will include a general COS and core TCM syndrome- set. Development of COSs for clinical trials of integrative medicine may help to standardize outcome reporting and reduce publication bias in the future.  相似文献   
32.
BackgroundWe examined how the relationship between education and latelife cognitive impairment (defined as a Mini Mental State Examination score below 24) is influenced by age, sex, ethnicity, and Apolipoprotein E epsilon 4 (APOE*4).MethodsParticipants were 30,785 dementia-free individuals aged 55–103 years, from 18 longitudinal cohort studies, with an average follow-up ranging between 2 and 10 years. Pooled hazard ratios were obtained from multilevel parametric survival analyses predicting cognitive impairment (CI) from education and its interactions with baseline age, sex, APOE*4 and ethnicity. In separate models, education was treated as continuous (years) and categorical, with participants assigned to one of four education completion levels: Incomplete Elementary; Elementary; Middle; and High School.ResultsCompared to Elementary, Middle (HR = 0.645, P = 0.004) and High School (HR = 0.472, P < 0.001) education were related to reduced CI risk. The decreased risk of CI associated with Middle education weakened with older baseline age (HR = 1.029, P = 0.056) and was stronger in women than men (HR = 1.309, P = 0.001). The association between High School and lowered CI risk, however, was not moderated by sex or baseline age, but was stronger in Asians than Whites (HR = 1.047, P = 0.044), and significant among Asian (HR = 0.34, P < 0.001) and Black (HR = 0.382, P = 0.016), but not White, APOE*4 carriers.ConclusionHigh School completion may reduce risk of CI associated with advancing age and APOE*4. The observed ethnoregional differences in this effect are potentially due to variations in social, economic, and political outcomes associated with educational attainment, in combination with neurobiological and genetic differences, and warrant further study.  相似文献   
33.
The treatment of advanced non-small cell lung cancer (NSCLC) may be changing, but the cisplatin-based doublet remains the foundation of treatment for the majority of patients with advanced NSCLC. In this respect, changes in practice to various aspects of cisplatin use, such as administration schedules and the choice of methods and frequency of monitoring for toxicities, have contributed to an incremental improvement in patient management and experience. Chemoresistance, however, limits the clinical utility of this drug in patients with advanced NSCLC. Better understanding of the molecular mechanisms of cisplatin resistance, identification of predictive markers and the development of newer, more effective and less toxic platinum agents is required. In addition to maximising potential benefits from advances in molecular biology and associated therapeutics, modification of existing cisplatin-based treatments can still lead to improvements in patient outcomes and experiences.  相似文献   
34.
ObjectiveDental plaque is a causative factor for oral disease and a potential reservoir for respiratory infection in the elderly. Therefore, there is a critical need for the development of effective methods to remove oral biofilm. The objective of this study was to investigate the effect of proteases on oral biofilm formation andremoval.DesignThe in vivo effect of actinidin, a cysteine protease, on the removal of tongue coating was assessed after orally taking a protease tablet. Effects of the proteases trypsin, papain and actinidin on Actinomyces monospecies biofilm and multispecies biofilm that was reconstructed using a plaque sample from the tongue coating were investigated using the microtiter plate method. Antimicrobial tests and limited proteolysis of fimbrial shaft proteins were also performed to clarify underlying mechanisms of oral biofilm removal.ResultsTablets containing actinidin removed tongue coating in elderly subjects. Oral Actinomyces biofilm was significantly reduced by the proteases papain, actinidin and trypsin. Papain and trypsin effectively digested the major fimbrial proteins, FimP and FimA, from Actinomyces. Actinidin, papain and trypsin reduced multispecies biofilm that was reconstructed in vitro. Papain and trypsin inhibited formation of multispecies biofilm in vitro.ConclusionsThis study shows that proteases reduced oral biofilm in vivo in elderly subjects and in vitro, and suggests that protease digests fimbriae and inhibits biofilm formation.  相似文献   
35.
36.
37.
Proper structure of the umbilical cord is important for the fetal development. We evaluated effects of toxic factors from tobacco smoke on fetal and umbilical cord morphometry. 109 women in weeks 29–40 of pregnancy (31 smokers with intrauterine growth restriction (IUGR); 28 non-smoking women with IUGR; 50 healthy pregnancies) were included. In smokers with IUGR, cotinine, cadmium and lead concentrations were significantly higher than in controls (mean 55.23 ng/l; 1.52 ng/ml; 14.85 ng/ml vs 1.07; 0.34; 9.42) and inverse correlation between lead concentration and uncoiled umbilical cord was significant (r = −0.80). In smokers with IUGR, area of Wharton’s jelly was increased compared to nonsmokers and controls. Inverse correlations occurred between cotinine and cadmium concentration and fetal percentile in smokers (r = −0.87; r = −0.87) and non-smokers (r = −0.47; r = −0.78) with IUGR. Exposure to tobacco smoke measured by cotinine, cadmium and lead concentration has an impact on fetal growth and umbilical cord morphometry and correlates with intensity of IUGR.  相似文献   
38.
39.
Three kinds of fish from a natural fishpond in the north of Taiwan were collected and analyzed in this study. The three species were non-predatory Ctenopharyn odon idellus, predatory Aristichthys nobilis and predatory Mylopharyngodon piceus. The activity concentrations of 90Sr in bone and edible flesh of fish, as well as in water and soil of fishpond were measured by using the radiochemical analysis. Additionally, the concentration of stable calcium in fish bone, [Ca]bone, and that of stable strontium in fish bone, [Sr]bone, were measured by ICP-AES. From the results, the concentration factors of 90Sr, CF(90Sr), in fish bone was no statistic difference between non-predatory and predatory fish. Besides, the accumulation of 90Sr in the non-predatory fish remarkably decreased with increasing the fish weight. As for the predatory fish, they both showed no statistically significant correlations between the 90Sr activity concentration and the fish weight. Regarding the activity concentrations of 90Sr in fish bone, all the fish were observed positively correlated with the measured [Sr]bone.  相似文献   
40.
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