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   2957篇
  免费   253篇
  国内免费   8篇
耳鼻咽喉   43篇
儿科学   81篇
妇产科学   106篇
基础医学   418篇
口腔科学   48篇
临床医学   336篇
内科学   667篇
皮肤病学   64篇
神经病学   246篇
特种医学   86篇
外科学   376篇
综合类   11篇
一般理论   3篇
预防医学   307篇
眼科学   43篇
药学   174篇
中国医学   2篇
肿瘤学   207篇
  2023年   61篇
  2022年   84篇
  2021年   199篇
  2020年   117篇
  2019年   147篇
  2018年   141篇
  2017年   99篇
  2016年   98篇
  2015年   113篇
  2014年   141篇
  2013年   154篇
  2012年   248篇
  2011年   220篇
  2010年   92篇
  2009年   76篇
  2008年   158篇
  2007年   143篇
  2006年   122篇
  2005年   105篇
  2004年   120篇
  2003年   108篇
  2002年   78篇
  2001年   41篇
  2000年   37篇
  1999年   27篇
  1998年   17篇
  1997年   19篇
  1996年   16篇
  1995年   13篇
  1994年   11篇
  1993年   6篇
  1992年   10篇
  1991年   9篇
  1990年   7篇
  1989年   11篇
  1988年   16篇
  1987年   12篇
  1986年   13篇
  1985年   12篇
  1984年   12篇
  1983年   6篇
  1982年   7篇
  1981年   10篇
  1980年   6篇
  1979年   11篇
  1974年   4篇
  1972年   7篇
  1971年   5篇
  1969年   7篇
  1968年   4篇
排序方式: 共有3218条查询结果,搜索用时 505 毫秒
41.
42.
43.
44.
Depressive disorder is a common consequence of interferon α treatment. An understanding of the aetiological processes involved is evolving. HPA axis abnormalities are clearly described in community depressive disorder and represent vulnerability to depression development. We explored whether pre-treatment HPA axis abnormalities influence depression emergence during interferon α treatment. We examined waking HPA axis response via salivary cortisol sampling in 44 non-depressed, chronic hepatitis C infected patients due to commence standard interferon α treatment. Hamilton depression scales and the structured clinical interview for DSM-IV major depressive disorder status were administered monthly during treatment. Major depressive disorder developed in 26 of 44 subjects during interferon-α treatment. The pre-treatment waking cortisol response over 1 h was significantly greater in the subsequent switch to depression group (F=4.23, p=0.046). The waking cortisol response pre-treatment with interferon α appears greater in those subsequently switching to depressive disorder during treatment. This waking response may join other vulnerability factors for depression emergence in this group. This model could prove a valuable tool in understanding non-iatrogenic depressive disorder in the general population and notably the role of cytokines.  相似文献   
45.
Aims: This pilot randomized comparative study investigated changes in motor performance and indices of neuroplasticity associated with occupation-based intervention and repetitive task practice in the recovery of occupational performance following stroke. Method: Sixteen participants received either occupation-based intervention or repetitive task practice for eight 55-minute sessions. Motor performance was measured by the Fugl Meyer Assessment (FMA), Stroke Impact Scale (SIS), the Canadian Occupational Performance Measure (COPM) and the Goal Attainment Scale (GAS). Indices of neuroplastic change were assessed by transcranial magnetic stimulation (TMS). Results: Both occupation-based intervention and repetitive task practice groups demonstrated significant changes on the FMA and the occupation-based group demonstrated significant changes on the GAS goals. Neurophysiological measures showed enlargement in TMS volume maps in the affected hemisphere for both groups. Conclusion: Occupation-based and repetitive task practice interventions can yield similar improvements in chronic stroke.  相似文献   
46.
Physical activity is partly regulated by automatic processes such as habits (ie, well-learned responses to cues), but it remains unclear what cues trigger these processes. This study examined the relations of physical activity automaticity and behavior with the consistency of people, activity, routine, location, time, and mood cues present upon initiation of physical activity behavior. Australian adults (N = 1,244, 627 female, M age = 55 years) reported their physical activity automaticity, behavior, and the degree of consistency of these cues each time they start a physical activity behavior. Multiple regression models, which accounted for gender and age, revealed that more consistent routine and mood cues were linked to more physical activity automaticity; whereas more consistent time and people cues were linked to more physical activity behavior. Interventions may more effectively translate into long-lasting physical activity habits if they draw people's attention to the salient cues of time, people, routine, and mood.  相似文献   
47.
The activity of five novel gyrase inhibitors was evaluated against 303 nonduplicate Pseudomonas aeruginosa strains collected from 53 North American institutions. The most active compound, GP-2, displayed MIC50 and MIC90 values of 1 and 2 μg/ml, respectively. Cross-resistance to other commercially available antipseudomonal compounds was not evident, as no major change was observed in the gyrase inhibitor MIC distribution when stratified by nonsusceptible phenotypes, including the fluoroquinolones and those isolates classified as multidrug resistant (MDR).  相似文献   
48.
49.
50.
The recognition of carbapenemase-producing Enterobacteriaceae (CPE) isolates is a major laboratory challenge, and their inappropriate or delayed detection may have negative impacts on patient management and on the implementation of infection control measures. We describe here a matrix-assisted laser desorption ionization−time of flight (MALDI-TOF)-based method to detect carbapenemase activity in Enterobacteriaceae. After a 20-min incubation of the isolate with 0.5 mg/ml imipenem at 37°C, supernatants were analyzed by MALDI-TOF in order to identify peaks corresponding to imipenem (300 Da) and an imipenem metabolite (254 Da). A total of 223 strains, 77 CPE (OXA-48 variants, KPC, NDM, VIM, IMI, IMP, and NMC-A) and 146 non-CPE (cephalosporinases, extended-spectrum β-lactamases [ESBLs], and porin defects), were tested and used to calculate a ratio of imipenem hydrolysis: mass spectrometry [MS] ratio = metabolite/(imipenem + metabolite). An MS ratio cutoff was statistically determined to classify strains as carbapenemase producers (MS ratio of ≥0.82). We validated this method first by testing 30 of our 223 isolates (15 CPE and 15 non-CPE) 10 times to calculate an intraclass correlation coefficient (ICC of 0.98), showing the excellent repeatability of the method. Second, 43 strains (25 CPE and 18 non-CPE) different from the 223 strains used to calculate the ratio cutoff were used as external controls and blind tested. They yielded sensitivity and specificity of 100%. The total cost per test is <0.10 U.S. dollars (USD). This easy-to-perform assay is time-saving, cost-efficient, and highly reliable and might be used in any routine laboratory, given the availability of mass spectrometry, to detect CPE.  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