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   33026篇
  免费   2096篇
  国内免费   261篇
耳鼻咽喉   440篇
儿科学   599篇
妇产科学   495篇
基础医学   4118篇
口腔科学   1549篇
临床医学   2712篇
内科学   8897篇
皮肤病学   397篇
神经病学   3361篇
特种医学   1302篇
外科学   5303篇
综合类   95篇
一般理论   6篇
预防医学   1342篇
眼科学   539篇
药学   1717篇
中国医学   73篇
肿瘤学   2438篇
  2023年   333篇
  2022年   277篇
  2021年   1245篇
  2020年   750篇
  2019年   1025篇
  2018年   1210篇
  2017年   962篇
  2016年   1071篇
  2015年   1141篇
  2014年   1472篇
  2013年   1797篇
  2012年   2791篇
  2011年   2681篇
  2010年   1514篇
  2009年   1379篇
  2008年   2158篇
  2007年   2270篇
  2006年   2044篇
  2005年   1848篇
  2004年   1654篇
  2003年   1512篇
  2002年   1309篇
  2001年   273篇
  2000年   253篇
  1999年   259篇
  1998年   240篇
  1997年   204篇
  1996年   153篇
  1995年   144篇
  1994年   123篇
  1993年   105篇
  1992年   118篇
  1991年   97篇
  1990年   80篇
  1989年   62篇
  1988年   91篇
  1987年   68篇
  1986年   55篇
  1985年   69篇
  1984年   60篇
  1983年   47篇
  1982年   44篇
  1981年   30篇
  1980年   25篇
  1979年   45篇
  1978年   32篇
  1977年   26篇
  1974年   25篇
  1973年   32篇
  1972年   33篇
排序方式: 共有10000条查询结果,搜索用时 421 毫秒
1.
2.
Whereas there is evidence that interpersonal communication, or conversation, influences predictors of alcohol consumption, the role of involvement in conversation effects remains unclear. This study explored how three aspects of involvement (topical relevance, or how relevant the topic of alcohol is; conversational relevance, or how relevant a conversation about alcohol is; and conversational effort, or how much effort people put into such a conversation), influence conversation effects. After assessing topical relevance, 46 same-sex dyads were requested to talk about the negative consequences of heavy drinking. Within each dyad, one participant was asked to take on an active talking role and the other participant a passive listening role. Next, conversational relevance, effort, and predictors of heavy drinking were measured. Results showed that participants who drank more alcohol found the topic of heavy drinking more relevant. This topical relevance increased conversational relevance and conversational effort. Conversational effort further increased when a talking role was assigned. Furthermore, participants who put more effort in the conversation and found it more relevant had more positive norms, identified more strongly with alcohol, and had higher intentions to drink. These findings suggest that more involvement in an alcohol-related conversation does not always lead to desirable outcomes.  相似文献   
3.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
4.
Colorectal cancer (CRC) screening programs help diagnose cancer precursors and early cancers and help reduce CRC mortality. However, currently recommended tests, the fecal immunochemical test (FIT) and colonoscopy, have low uptake. There is therefore a pressing need for screening strategies that are minimally invasive and consequently more acceptable to patients, most likely blood based, to increase early CRC identification. MicroRNAs (miRNAs) released from cancer cells are detectable in plasma in a remarkably stable form, making them ideal cancer biomarkers. Using plasma samples from FIT-positive (FIT+) subjects in an Italian CRC screening program, we aimed to identify plasma circulating miRNAs that detect early CRC. miRNAs were initially investigated by quantitative real-time PCR in plasma from 60 FIT+ subjects undergoing colonoscopy at Fondazione IRCCS Istituto Nazionale dei Tumori, then tested on an internal validation cohort (IVC, 201 cases) and finally in a large multicenter prospective series (external validation cohort [EVC], 1121 cases). For each endoscopic lesion (low-grade adenoma [LgA], high-grade adenoma [HgA], cancer lesion [CL]), specific signatures were identified in the IVC and confirmed on the EVC. A two-miRNA-based signature for CL and six-miRNA signatures for LgA and HgA were selected. In a multivariate analysis including sex and age at blood collection, the areas under the receiver operating characteristic curve (95% confidence interval) of the signatures were 0.644 (0.607–0.682), 0.670 (0.626–0.714) and 0.682 (0.580–0.785) for LgA, HgA and CL, respectively. A miRNA-based test could be introduced into the FIT+ workflow of CRC screening programs so as to schedule colonoscopies only for subjects likely to benefit most.  相似文献   
5.
Graefe's Archive for Clinical and Experimental Ophthalmology - To estimate the impact of delayed care during the coronavirus disease 2019 (COVID-19) pandemic on the outcomes of patients with...  相似文献   
6.
7.
8.
9.
This meta-analysis focuses on the accuracy of upgrading to clinically significant prostate cancer (PCa) by multiparametric magnetic resonance imaging-targeted biopsy (MRI-TB) versus systematic biopsy (SB). We searched the Medline, Embase, Cochrane Central Register of Controlled Trials, Web of Science, Scopus, and Literatura Latino Americana em Ciências da Saúde databases through January 2020 for comparative, retrospective/prospective, paired-cohort, and randomized clinical trials with paired comparisons. The population consisted of patients with low-risk PCa in active surveillance with at least 1 index lesion on imaging. We evaluated the quality of evidence by using the Quality Assessment of Diagnostic Accuracy Studies-2 score. Group comparisons considered the differences between the area under the curve summary receiver operating characteristic curve in a 2-tailed method. We also compared the positive predictive value of the best single method (MRI-TB or SB) and the referral study test (combined biopsy, a combination of MRI-TB and SB). The meta-analysis included 6 studies enrolling 741 patients. The pooled sensitivity for the 2 groups was 0.79 (95% confidence interval, 0.74-0.83; I2 = 75%) and 0.67 (95% confidence interval, 0.63-0.74; I2 = 55.4%), respectively. The area under the curve for the MRI-TB and SB groups were 0.99 and 0.92 (P < .001), respectively. The positive predictive value for the MRI-TB and combined biopsy groups were similar. The accumulated evidence suggests better results for MRI-TB compared with SB. Therefore, use of MRI-TB alone may be preferable in patients in active surveillance harboring low-risk PCa.  相似文献   
10.
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