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   6079篇
  免费   264篇
  国内免费   52篇
耳鼻咽喉   36篇
儿科学   147篇
妇产科学   192篇
基础医学   590篇
口腔科学   92篇
临床医学   665篇
内科学   1832篇
皮肤病学   56篇
神经病学   636篇
特种医学   183篇
外科学   764篇
综合类   23篇
预防医学   257篇
眼科学   103篇
药学   377篇
中国医学   27篇
肿瘤学   415篇
  2023年   40篇
  2022年   99篇
  2021年   135篇
  2020年   86篇
  2019年   112篇
  2018年   138篇
  2017年   96篇
  2016年   105篇
  2015年   145篇
  2014年   209篇
  2013年   265篇
  2012年   427篇
  2011年   417篇
  2010年   250篇
  2009年   269篇
  2008年   440篇
  2007年   454篇
  2006年   486篇
  2005年   426篇
  2004年   363篇
  2003年   287篇
  2002年   287篇
  2001年   65篇
  2000年   47篇
  1999年   55篇
  1998年   63篇
  1997年   52篇
  1996年   52篇
  1995年   33篇
  1994年   23篇
  1993年   36篇
  1992年   52篇
  1991年   35篇
  1990年   29篇
  1989年   26篇
  1988年   26篇
  1987年   26篇
  1986年   20篇
  1985年   22篇
  1984年   27篇
  1983年   22篇
  1982年   17篇
  1981年   19篇
  1980年   12篇
  1979年   10篇
  1978年   8篇
  1977年   7篇
  1974年   10篇
  1971年   8篇
  1969年   6篇
排序方式: 共有6395条查询结果,搜索用时 15 毫秒
81.
82.
A specific subset of micro RNAs (miRs), including miR-133 and miR-206, is specifically expressed in muscle tissue, so that they are currently defined as muscular miRs (myomiRs). To further elucidate the role of myomiRs in muscle biology, we measured miR-133a and miR-206 in plasma of 28 middle-age recreational athletes. The study population consisted of 28 middle aged, recreation athletes (11 women and 17 men; mean age, 46?years) who completed a 21.1?km, half-marathon. The plasma concentration of miR-133a and miR-206, the serum concentration of creatine kinase (CK) and high-sensitivity (HS) cardiac troponin T (cTnT), as well as capillary lactate, were measured before and immediately after the run. The median serum concentration of total CK (257 versus 175?U/L; p?p??4; p??4; p?=?.001) were considerably increased immediately after the half-marathon run. In multivariate analysis only post-exercise capillary lactate was found to be independently associated with running time. A significant and independent correlation was observed between plasma variations of the two miRs, but not with other physiological or laboratory parameters. The results of this study suggest that the biological significance of miR-133a and 206 variation after middle-distance running parallels but not overlaps the release of biomarkers of nonspecific tissue damage. Enhanced plasma values of these myomiRs may hence reflect a physiological response to high-intensity and/or prolonged exercise rather than tissue injury.  相似文献   
83.

Background

In 2007, the Government of Pakistan introduced a new cadre of community midwives (CMWs) to address low skilled birth attendance rates in rural areas; this workforce is located in the private-sector. There are concerns about the effectiveness of the programme for increasing skilled birth attendance as previous experience from private-sector programmes has been sub-optimal. Indonesia first promoted private sector midwifery care, but the initiative failed to provide universal coverage and reduce maternal mortality rates.

Methods

A clustered, stratified survey was conducted in the districts of Jhelum and Layyah, Punjab. A total of 1,457 women who gave birth in the 2 years prior to the survey were interviewed. χ2 analyses were performed to assess variation in coverage of maternal health services between the two districts. Logistic regression models were developed to explore whether differentials in coverage between the two districts could be explained by differential levels of development and demand for skilled birth attendance. Mean cost of childbirth care by type of provider was also calculated.

Results

Overall, 7.9% of women surveyed reported a CMW-attended birth. Women in Jhelum were six times more likely to report a CMW-attended birth than women in Layyah. The mean cost of a CMW-attended birth compared favourably with a dai-attended birth. The CMWs were, however, having difficulty garnering community trust. The majority of women, when asked why they had not sought care from their neighbourhood CMW, cited a lack of trust in CMWs’ competency and that they wanted a different provider.

Conclusions

The CMWs have yet to emerge as a significant maternity care provider in rural Punjab. Levels of overall community development determined uptake and hence coverage of CMW care. The CMWs were able to insert themselves into the maternal health marketplace in Jhelum because of an existing demand. A lower demand in Layyah meant there was less ‘space’ for the CMWs to enter the market. To ensure universal coverage, there is a need to revisit the strategy of introducing a new midwifery workforce in the private sector in contexts of low demand and marketing the benefits of skilled birth attendance.
  相似文献   
84.
Journal of Thrombosis and Thrombolysis - No study investigated the possible detrimental effect of stress hyperglycemia on patients affected acute ischemic stroke (AIS) undergoing intravenous...  相似文献   
85.
86.
87.
OBJECTIVE: Vaccination against influenza in patients with chronic lymphoproliferative disorders (CLPD) and multiple myeloma (MM) is still a matter of clinical uncertainty. The aim of this study was to determine the safety, immunogenicity and clinical response to a commercially available vaccine against influenza in a group of such patients. METHODS: Thirty-four patients with CLPD and MM and 34 immunologically normal subjects were vaccinated with the same vaccine against influenza. Patients were observed during the epidemic season from October 1999 to April 2000, and monitored for side-effects of the vaccine, seroprotection and seroconversion after vaccination. The prevaccination level of immunoglobulins was also determined. Occurrence of influenza episodes was demonstrated with the positive isolation of a viral strain from a pharyngeal swab. RESULTS: No patient had untoward reactions to the vaccine used. Seroconversion and seroprotection were up to the standard established by the European Agency for the Evaluation of Medicinal Products. Only one patient developed influenza during follow-up. CONCLUSIONS: Influenza vaccine is effective and well tolerated in patients with CLPD and MM. No contraindications exist for its use, and it should become a routine practice, in order to prevent serious complications during the influenza epidemic season.  相似文献   
88.
89.
Current feature-based semantic memory models assume that the semantic representations of concepts differ systematically across living and nonliving categories and that such differences account for the emergence of category-specific semantic deficits in brain-damaged people. To assess some of the different models' main assumptions about structural differences at the semantic feature level in the two major semantic domains, we administrated a feature-listing task to normal young volunteers on 64 concepts drawn from living and nonliving semantic categories. We investigated whether feature correlation, a variable with a crucial role in the emergence of category-specific deficits, should be computed as a concept-dependent or as a concept-independent measure, and we chose the former. We also addressed the issue of a psychological counterpart of feature production frequency. Finally, we analysed the database obtained from the feature-listing tasks, looked at cross-domain differences for correlation, feature frequency, distinctiveness, and feature type, and discussed the implications of these findings for current semantic memory models.  相似文献   
90.
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