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   755篇
  免费   47篇
耳鼻咽喉   6篇
儿科学   26篇
妇产科学   5篇
基础医学   122篇
口腔科学   24篇
临床医学   74篇
内科学   130篇
皮肤病学   6篇
神经病学   132篇
特种医学   32篇
外科学   88篇
综合类   19篇
预防医学   47篇
眼科学   2篇
药学   41篇
肿瘤学   48篇
  2023年   6篇
  2022年   15篇
  2021年   15篇
  2020年   10篇
  2019年   18篇
  2018年   21篇
  2017年   7篇
  2016年   10篇
  2015年   11篇
  2014年   17篇
  2013年   22篇
  2012年   31篇
  2011年   31篇
  2010年   11篇
  2009年   17篇
  2008年   29篇
  2007年   21篇
  2006年   24篇
  2005年   26篇
  2004年   21篇
  2003年   21篇
  2002年   20篇
  2001年   18篇
  2000年   23篇
  1999年   19篇
  1998年   14篇
  1997年   7篇
  1996年   7篇
  1995年   7篇
  1994年   7篇
  1993年   12篇
  1992年   20篇
  1991年   26篇
  1990年   17篇
  1989年   25篇
  1988年   29篇
  1987年   17篇
  1986年   18篇
  1985年   15篇
  1984年   15篇
  1983年   11篇
  1982年   6篇
  1981年   9篇
  1980年   6篇
  1979年   10篇
  1978年   5篇
  1977年   13篇
  1976年   5篇
  1975年   9篇
  1970年   4篇
排序方式: 共有802条查询结果,搜索用时 78 毫秒
61.
HIV-positive lactating women may be at high risk of weight loss due to increased caloric requirements and postpartum physiological weight loss. Ten percent weight loss is associated with a higher risk of mortality in HIV-positive patients and this alone is a criterion for highly active antiretroviral therapy (HAART) initiation where CD4 counts are not available. However, no study has investigated this association in lactating postpartum women. We investigated whether 10% weight loss predicts death in postpartum HIV-positive women. A total of 9207 HIV-negative and 4495 HIV-positive mothers were recruited at delivery. Women were weighed at 6 weeks, 3 months, and every 3 months thereafter for up to 24 months postpartum and data on mortality up to 2 years were collected. The median duration of breastfeeding was longer than 18 months. Among HIV-positive women, the independent predictors of ≥10% weight loss were CD4 cell count, body mass index, and household income. Mortality was up to 7.12 (95% CI 3.47-14.61) times higher in HIV-positive women with ≥10% weight loss than those without weight loss. Ten percent weight loss in postpartum lactating HIV-positive women was significantly predictive of death. Our findings suggest that 10% weight loss is an appropriate criterion for HAART initiation among postpartum breastfeeding women.  相似文献   
62.
BACKGROUND: The efficacy and safety of mometasone furoate aqueous nasal spray (MFNS; Nasonex) 200 microg once daily for the treatment and prophylaxis of seasonal allergic rhinitis (SAR) and treatment of perennial rhinitis have been demonstrated in adults. However, the dose response of MFNS in pediatric patients has not yet been characterized. OBJECTIVE: This study was conducted to determine the dose-response relationship of 3 different doses of MFNS in a pediatric population. METHODS: This was a multicenter, double-blind, active- and placebo-controlled study of 679 children 6 to 11 years of age with histories of SAR and documented positive skin test responses. Patients were randomized to one of the following treatment groups for 4 weeks: MFNS 25 microgram once daily, MFNS 100 microgram once daily, MFNS 200 microgram once daily, beclomethasone dipropionate 84 microgram twice daily (168 microgram/day), or placebo. Physician evaluations were performed at days 4, 8, 15, and 29, and patient evaluations were analyzed for days 1 to 15 and 16 to 29. RESULTS: The mean reduction from baseline in physician-evaluated total nasal symptom scores at day 8 (the primary efficacy variable) was significantly greater in the MFNS and beclomethasone dipropionate groups than in the placebo group (P 相似文献   
63.
Yao S  Zhu Y  Zhu G  Augustine M  Zheng L  Goode DJ  Broadwater M  Ruff W  Flies S  Xu H  Flies D  Luo L  Wang S  Chen L 《Immunity》2011,34(5):729-740
CD28 and CTLA-4 are cell surface cosignaling molecules essential for the control of T?cell activation upon the engagement of their ligands B7-1 and B7-2 from antigen-presenting cells. By employing a receptor array assay, we have demonstrated that B7-H2, best known as the ligand of inducible costimulator, was a ligand for CD28 and CTLA-4 in human, whereas these interactions were not conserved in mouse. B7-H2 and B7-1 or B7-2 interacted with CD28 through distinctive domains. B7-H2-CD28 interaction was essential for?the costimulation of human T?cells' primary responses to allogeneic antigens and memory recall responses. Similar to B7-1 and B7-2, B7-H2 costimulation via CD28 induced survival factor Bcl-xL, downregulated cell cycle inhibitor p27(kip1), and triggered signaling cascade of ERK and AKT kinase-dependent pathways. Our findings warrant re-evaluation of CD28 and CTLA-4's functions previously attributed exclusively to B7-1 and B7-2 and have important implications in therapeutic interventions against human diseases.  相似文献   
64.
Adolescent mothering was investigated in 95 adolescent mothers who were 15-19 years old. Adolescent mothering behavior was found to be related to age of the mother, grade in school, sex of the infant and maintenance of a relationship with the baby's father. Specific deficits were noted in areas of social, emotional and cognitive growth-fostering behavior and in response to infant distress. Health teaching, support, reinforcement and anticipatory guidance were some implications for nursing.  相似文献   
65.
A group of 259 normal adults were administered the San Diego Neuropsychological Test Battery. Factor analysis of the SDNB supported the construct validity of the battery according to a Luria-based functional systems assessment approach. Using expert ratings to interpret the obtained factor loadings, the following factors were identified: (a) arousal, (b) mnestic processes, (c) complex intelligence, and (d) planning. A second factor analysis of the SDNB, using a sample of 100 schizophrenic and head injured cases, achieved a factor structure very similar to that of the normal sample, offering further empirical support for a functional assessment approach with clinical populations. The clinical factor analysis yielded slightly different proportions of variance contributed by the test measures and two planning factors. The results are discussed as they relate to Luria's qualitative analysis of cortical organization applied to a quantitative methodology.  相似文献   
66.
67.
Heterotopic brain in the nasopharynx   总被引:2,自引:0,他引:2  
  相似文献   
68.
69.
70.
High-mass matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with chemical cross-linking has the ability to monitor the ligand-dependent dimerization of the human estrogen receptor α ligand binding domain (hERα LBD) in solution. Because only ER ligands enhance the homodimer abundance, we evaluated the ability of this label-free approach for identifying endocrine disrupting compounds (EDCs) in a high-throughput manner. This was achieved by combining an automated liquid handler with an automated MS acquisition procedure, which allowed a five-fold gain in operator time compared to a fully manual approach. To detect ligand binding with enough confidence, the receptor has to be incubated with at least a 10 μM concentration of the test compound. Based on the increase of the measured homodimer intensity, eight compounds with a relative binding affinity (RBA, relative to the natural hormone estradiol) >7% were identified as ER ligands among the 28 chemicals tested. Two other compounds, quercetin and 4-tert-amylphenol, were also identified as ER ligands, although their RBAs have been reported to be only 0.01% and 0.000055%, respectively. This suggests that these two ligands have a higher affinity for hERα LBD than reported in the literature. The high-mass MALDI approach thus allows identifying high affinity EDCs in an efficient way.  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