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   2434篇
  免费   121篇
  国内免费   13篇
耳鼻咽喉   11篇
儿科学   35篇
妇产科学   86篇
基础医学   414篇
口腔科学   94篇
临床医学   181篇
内科学   380篇
皮肤病学   120篇
神经病学   225篇
特种医学   79篇
外科学   389篇
综合类   5篇
预防医学   72篇
眼科学   48篇
药学   144篇
中国医学   32篇
肿瘤学   253篇
  2023年   10篇
  2022年   36篇
  2021年   74篇
  2020年   32篇
  2019年   43篇
  2018年   46篇
  2017年   41篇
  2016年   63篇
  2015年   103篇
  2014年   109篇
  2013年   155篇
  2012年   222篇
  2011年   221篇
  2010年   131篇
  2009年   111篇
  2008年   150篇
  2007年   133篇
  2006年   121篇
  2005年   115篇
  2004年   105篇
  2003年   83篇
  2002年   69篇
  2001年   74篇
  2000年   72篇
  1999年   63篇
  1998年   19篇
  1997年   15篇
  1996年   13篇
  1995年   14篇
  1994年   11篇
  1993年   8篇
  1992年   15篇
  1991年   11篇
  1990年   10篇
  1989年   9篇
  1988年   13篇
  1987年   14篇
  1986年   6篇
  1985年   4篇
  1984年   4篇
  1979年   3篇
  1977年   2篇
  1975年   1篇
  1974年   3篇
  1973年   1篇
  1972年   1篇
  1971年   1篇
  1966年   1篇
  1964年   1篇
  1960年   1篇
排序方式: 共有2568条查询结果,搜索用时 578 毫秒
31.
Although rates of late‐stage melanoma are rising in Hispanics, particularly those living in high ultraviolet light environments, little is known about the prevalence of sun protective behaviors in Hispanic children. We analyzed baseline data including frequency of sunburn, sun protective behaviors, level of U.S. acculturation, and skin phototype from a cross‐sectional survey of 2003 Hispanic elementary school children in Los Angeles, California, who participated in a skin cancer prevention intervention. Although the Hispanic children reported frequently engaging in some sun protective behaviors, they also had a high rate of sunburn (59%) that exceeded previous national estimates for non‐Hispanic white children (43%). Fewer U.S.‐acculturated children reported more frequent shade‐seeking at home (P = .02), along with less shade‐seeking at school (P = .001) and more sunscreen use at school (P = .02). The surprisingly high rate of sunburn in Hispanic children suggests that the way in which they are practicing sun protection is not preventing sunburns. Sun safety interventions should be targeted toward Hispanic youth to provide them with practical methods of effective sun protection, in addition to education on the risks of high sun exposure.  相似文献   
32.
High residual platelet activation (HRPA) after ADP stimuli has associated with recurrent vascular events in acute atherothrombosis with the use of antiplatelet agents (APAs). However, there has been little evidence supporting this association in acute ischemic stroke (AIS). In this study, we evaluated the influences of HRPR after ADP stimuli on the 1-year incidence of recurrent cardiovascular events and mortality in AIS with APAs. We conducted an observational, referral center cohort study on 968 AIS patients with APAs from January 2010 to December 2013 who were evaluated using optical platelet aggregometry (OPA). All patients received the dual APA combination of aspirin and clopidogrel or aspirin alone. We evaluated their platelet function 5 days after hospital admission using OPA. HRPR after ADP stimuli was defined as platelet aggregation of 70 % or greater according to OPA after 10 µM ADP stimuli. The primary endpoint was a composite of all causes of death, myocardial infarction, and stroke at the 1-year follow-up. The secondary endpoints were each component of the primary endpoint. The event rate of primary endpoint was 11.3 % (109/968). Its rate was significantly higher in the patients with HRPR (16.7 %) than in those without (9.7 %). HPRP was independently associated with the primary endpoint (OR = 1.97, CI 1.22–3.18, p < 0.01). According to the AIS subtype, the presence of HRPR was independently significant for the occurrence of the primary endpoint in the large artery atherosclerosis (LAA) subtype only (OR = 2.26, CI 1.15–4.45, p = 0.02). In this study, the presence of HRPR after ADP stimuli is associated with a poor long-term outcome after acute ischemic stroke. In particular, the influence of this factor might be more prominent in LAA compared with other types of AIS.  相似文献   
33.
A method to fabricate micropatterns of non‐circular droplets of a self‐assembled block copolymer by solvent‐assisted wetting on chemically periodic surface is presented. The block copolymer is dewetted on a topographic pre‐pattern to form an array of microdroplets with a sphere‐capped shape and circular contact line. The droplets are then transferred onto a chemically periodic Au line pattern microcontact‐printed with two types of self‐assembled monolayers (SAMs). Solvent vapor application provides sufficient mobility to the block copolymer molecules to induce spreading of the transferred droplets, resulting in two types of non‐circular microdroplet growth. The growth behavior depends on the size of initial droplets relative to periodic line width and on the initial registries of as‐transferred droplets.  相似文献   
34.
35.
36.
37.
38.
39.
40.
Nerve injury especially inferior alveolar nerve (IAN) is the one of the complications that occur when the mandibular third molar (M3) is extracted and in case of high risk patients, coronectomy might be an alternative to tooth extraction. The purpose of this retrospective study was to analyze root migration and its influencing factors at 6 months after coronectomy in both 2- and 3-dimensions using periapical view and cone-beam computed tomography (CBCT). We analyzed 33 cases of root remnant after coronectomy and measured the amount of migration in CBCT. The following factors that could possibly affect root migration were also analyzed: age, gender, number of M3 roots, shape of M3s, Pell, and Gregory classification, mesiodistal (MD) angulation, buccolingual (BL) angulation, contact point with the second molar, root curvature, and complete removal of the coronal portion. Migration of greater than 2 mm was found in 64% of the roots in the 2-dimensional (2D) analysis, and the average root migration was 4.11 mm in the 3-dimensional (3D) analysis. The factors affecting migration were the root morphology, complete removal of the coronal portion, impaction depth, and MD angulation in the 2D analysis, and MD and BL angulation in the 3D analysis. Ensuring sufficient space for root migration especially considering angulation, depth and complete removal of the coronal portion might be important factors after coronectomy of the M3. Root remnant after coronectomy of M3 may migrate in young patients who has sufficient empty coronal space and this may reduce the nerve damage by the separation of IAN and M3.  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