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   3712903篇
  免费   310439篇
  国内免费   13769篇
耳鼻咽喉   50917篇
儿科学   118452篇
妇产科学   97254篇
基础医学   581123篇
口腔科学   102911篇
临床医学   331741篇
内科学   662035篇
皮肤病学   95208篇
神经病学   317297篇
特种医学   148675篇
外国民族医学   497篇
外科学   572853篇
综合类   113774篇
现状与发展   23篇
一般理论   2378篇
预防医学   309706篇
眼科学   85820篇
药学   259938篇
  22篇
中国医学   10129篇
肿瘤学   176358篇
  2021年   55081篇
  2020年   35094篇
  2019年   58003篇
  2018年   71454篇
  2017年   54481篇
  2016年   60268篇
  2015年   74266篇
  2014年   108538篇
  2013年   173646篇
  2012年   97511篇
  2011年   97944篇
  2010年   117840篇
  2009年   122141篇
  2008年   85757篇
  2007年   89093篇
  2006年   99995篇
  2005年   95110篇
  2004年   97692篇
  2003年   88160篇
  2002年   78001篇
  2001年   120846篇
  2000年   115148篇
  1999年   111710篇
  1998年   67029篇
  1997年   64584篇
  1996年   62582篇
  1995年   58196篇
  1994年   52353篇
  1993年   48887篇
  1992年   82948篇
  1991年   79404篇
  1990年   75960篇
  1989年   74634篇
  1988年   69451篇
  1987年   68147篇
  1986年   64935篇
  1985年   64810篇
  1984年   56594篇
  1983年   51289篇
  1982年   44765篇
  1981年   41923篇
  1980年   39522篇
  1979年   48966篇
  1978年   40959篇
  1977年   36780篇
  1976年   34083篇
  1975年   32850篇
  1974年   35537篇
  1973年   34201篇
  1972年   31689篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
There is an increasing number of effective therapies for fracture prevention in adults at risk of osteoporosis. However, shortcomings in the evidence underpinning our management of osteoporosis still exist. Evidence of antifracture efficacy in the groups of patients who most commonly use calcium and vitamin D supplements is lacking, the safety of calcium supplements is in doubt, and the safety and efficacy of high doses of vitamin D give cause for concern. Alendronate, risedronate, zoledronate and denosumab have been shown to prevent spine, nonspine and hip fractures; in addition, teriparatide and strontium ranelate prevent both spine and nonspine fractures, and raloxifene and ibandronate prevent spine fractures. However, most trials provide little information regarding long‐term efficacy or safety. A particular concern at present is the possibility that oral bisphosphonates might cause atypical femoral fractures. Observational data suggest that the incidence of this type of fracture increases steeply with duration of bisphosphonate use, resulting in concern that the benefit–risk balance may become negative in the long term, particularly in patients in whom the osteoporotic fracture risk is not high. Therefore, reappraisal of ongoing use of bisphosphonates after about 5 years is endorsed by expert consensus, and ‘drug holidays’ should be considered at this time. Further studies are needed to guide clinical practice in this area.  相似文献   
62.
The value of adding simeprevir (SMV) vs placebo (PBO) to peginterferon and ribavirin (PR) for treatment of chronic hepatitis C virus infection was examined using patient‐reported outcomes (PROs); further, concordance of PROs with virology endpoints and adverse events (AEs) was explored. Patients (= 768 SMV/PR,= 393 PBO/PR) rated fatigue (FSS), depressive symptoms (CES‐D) and functional impairment (WPAI: Hepatitis C Productivity, Daily Activity and Absenteeism) at baseline and throughout treatment in three randomised, double‐blind trials comparing the addition of SMV or PBO during initial 12 weeks of PR. PR was administered for 48 weeks (PBO group) and 24/48 weeks (SMV group) using a response‐guided therapy (RGT) approach. Mean PRO scores (except Absenteeism) worsened from baseline to Week 4 to the same extent in both groups but reverted after Week 24 for SMV/PR and only after Week 48 for PBO/PR. Accordingly, there was a significantly lower area under the curve (baseline–Week 60, AUC60) and fewer weeks with clinically important worsening of scores in the SMV/PR group at any time point. Incidences of patients with fatigue and anaemia AEs were similar in both groups, but FSS scores showed that clinically important increases in fatigue lasted a mean of 6.9 weeks longer with PBO/PR (P < 0.001). PRO score subgroup analysis indicated better outcomes for patients who met the criteria for RGT or achieved sustained virological response 12 weeks post‐treatment (SVR12); differences in mean PRO scores associated with fibrosis level were only observed with PBO/PR. Greater efficacy of SMV/PR enabled reduced treatment duration and reduced time with PR‐related AEs without adding to AE severity.  相似文献   
63.
64.
65.
66.
The aim of the study was to determine the effect of β-glucan on the cytotoxicity and genotoxicity of polypectomized patient's fecal water (FW). Polypectomized volunteers (n = 69) were randomly assigned to consume bread with or without β-glucan, for 3 months. FW was collected at the beginning (t = 0), the 30th and 90th day and 2 wk after the intervention. Cytotoxicity and genotoxicity were estimated on Caco-2 cells, using trypan blue exclusion test and comet assay, respectively. Gastrointestinal symptoms were recorded and subjects kept a 3-day food diary at baseline and after completion. Trypan blue exclusion test revealed cell survival of approximately 87% after incubation with FW. The FW samples showed 49% genotoxicity at the baseline. Genotoxicity in the intervention group decreased during the trial reaching statistical significance on the 90th day compared to control. An increase was noticed 2 wk after the trial, but it still remained significantly lower compared to control. Group-specific analysis for β-glucan also revealed significant decrease in the genotoxicity on the 90th day compared to baseline. β-glucan ingestion in polypectomized patients significantly decreased the genotoxicity of their FW. Our findings suggest that β-glucan consumption could possibly provide protection against colon cancer development.  相似文献   
67.
68.
69.
70.
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