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   882143篇
  免费   53547篇
  国内免费   1059篇
耳鼻咽喉   12263篇
儿科学   28212篇
妇产科学   23409篇
基础医学   124778篇
口腔科学   24028篇
临床医学   77963篇
内科学   166341篇
皮肤病学   19699篇
神经病学   66494篇
特种医学   34909篇
外国民族医学   166篇
外科学   132484篇
综合类   17831篇
现状与发展   1篇
一般理论   216篇
预防医学   61430篇
眼科学   20155篇
药学   70098篇
  23篇
中国医学   2238篇
肿瘤学   54011篇
  2021年   6432篇
  2019年   6753篇
  2018年   9478篇
  2017年   7470篇
  2016年   8393篇
  2015年   9255篇
  2014年   12611篇
  2013年   18358篇
  2012年   25460篇
  2011年   26748篇
  2010年   15574篇
  2009年   14607篇
  2008年   24740篇
  2007年   26466篇
  2006年   26920篇
  2005年   25482篇
  2004年   24534篇
  2003年   23448篇
  2002年   22684篇
  2001年   48490篇
  2000年   49494篇
  1999年   41159篇
  1998年   10076篇
  1997年   8990篇
  1996年   8948篇
  1995年   8423篇
  1994年   7595篇
  1993年   7227篇
  1992年   30548篇
  1991年   29259篇
  1990年   28786篇
  1989年   27752篇
  1988年   24875篇
  1987年   24186篇
  1986年   22839篇
  1985年   21364篇
  1984年   15504篇
  1983年   13038篇
  1982年   7109篇
  1979年   13889篇
  1978年   9187篇
  1977年   8307篇
  1976年   7164篇
  1975年   8049篇
  1974年   9411篇
  1973年   9086篇
  1972年   8714篇
  1971年   8222篇
  1970年   7488篇
  1969年   7184篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Tuberculosis (TB) is described as lethal disease in the world. Resistant to TB drugs is the main reason to have unfavourable outcomes in the treatment of TB. Therefore, new agents to replace existing drugs are urgently needed. Previous reports suggested that InhA inhibitors, an enoyl-ACP-reductase, might provide auspicious candidates which can be developed into novel antitubercular agents. In this review, we explain the role of InhA in the resistance of isoniazid. Furthermore, five classes of InhA inhibitors, which display novel binding modes and deliver evidence of their prosperous target engagement, have been debated.  相似文献   
92.
93.
94.
95.
96.

Objectives

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

Methods

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

Results

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

Conclusion

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.
  相似文献   
97.

Background/Objectives

Falls are one of the most prevalent health issues facing older adults. This study examines the validity of the Toulouse-St. Louis University Mini Falls Assessment (TSLUMFA). Objectives were to validate the TSLUMFA by testing if it differentiates between prior non fallers (n=80) and fallers (n=23), and predicts future falls as well as or better than the gold standard Tinetti Gait and Balance Instrument (TGBI). Examine if the subset of FRAIL Scale items on the TSLUMFA distinguishes between previous non fallers (n=75) and fallers (n=20), and predicts future falls as well as or better than the TGBI. Identify TSLUMFA cut offs scores for fall risk.

Design

Prospective validation study.

Setting

Participants were ambulatory patients presenting to the SLU Geriatrics Clinic.

Participants

103 ambulatory older adults.

Measurements

Fall risk was assessed using the three assessments. Outcome measures were previous falls and follow up falls.

Results

TSLUMFA, FRAIL, and TGBI differentiated between previous fallers and non fallers. A TSLUMFA score <23 stratified patients as moderate risk (Sensitivity=0.806 Specificity=0.776) and a score <21 stratified patients as high risk (Sensitivity=0.929 Specificity=0.897). 78% of patients (n=80) participated in follow up and 20% (n=16) of these patients fell during follow up. TSLUMFA and TGBI absolute scores were lower among patients who fell during the follow up period versus non fallers but the observed differences were not statistically significant (TSLUMFA P=0.123 and TGBI P=0.074).

Conclusion

This study validated the TSLUMFA and FRAIL. No test predicted falls with statistical significance (most likely due to the low follow up participation) but a positive trend was seen. Clinical recommendations from this study are to use the FRAIL as an initial fall screen and patients scoring > 3 should be analyzed by TSLUMFA. The TSLUMFA’s advantage is that it pinpoints areas that will directly benefit from therapy to reduce falls.
  相似文献   
98.
99.
Investigators postulated that early-life exposure to organic mercury (Hg) significantly increases the risk of childhood neurodevelopmental disorders (NDs). The Vaccine Adverse Event Reporting System database was utilized to conduct a hypothesis testing case-control study by evaluating 3486 total adverse event reports reported following Haemophilus influenza type b (Hib) vaccination. Exposed subjects received a Thimerosal-containing formulation (HIBTITER?, Wyeth-Lederle), while unexposed subjects received a Thimerosal-free formulation (PEDVAXHIB?, Merck). Subjects were included if they received either of these two Hib vaccine formulations between 1995 and 1999. Cases were defined as adverse event reports with a reported outcome of autism, developmental delay, psychomotor delay, or NDs in general. Cases with reported outcomes of febrile convulsions, pyrexia, or injection site pain, all of which have no biologically plausible relation to Hg exposure, were also examined. Controls were defined as adverse event reports without any mention of the specific case outcome examined. Cases of reported autism (odds ratio (OR)?=?2.75, p?<?0.02), developmental delay (OR?=?5.39, p?<?0.01), psychomotor disorder (OR?=?2.38, p?<?0.03), and neurodevelopmental disorder in general (OR?=?2.70, p?<?0.001) were each significantly more likely than their respective controls to receive Thimerosal-containing Hib vaccine than Thimerosal-free Hib vaccine. Significant effects for neurodevelopmental disorder in general were observed for males (OR?=?2.52, p?<?0.005), but not females when separated by gender. For the outcomes that had no biologically plausible relation to Hg exposure, the cases were no more likely than their respective controls to receive Thimerosal-containing Hib vaccine than Thimerosal-free Hib vaccine. This study provides suggestive evidence of an association between Thimerosal and neurodevelopmental outcomes and provides support for carrying out additional well-designed studies examining the association between Thimerosal-containing vaccines and a wide range of neurodevelopmental outcomes.  相似文献   
100.

Background

The prevalence of knee osteoarthritis is increasing worldwide. Obesity is an important modifiable risk factor for both the incidence and progression of knee osteoarthritis. Consequently, international guidelines recommend all patients with knee osteoarthritis who are overweight receive support to lose weight. However, few overweight patients with this condition receive care to support weight loss. Telephone-based interventions are one potential solution to provide scalable care to the many patients with knee osteoarthritis. The objective of this study is to evaluate, from a societal perspective, the cost-utility and cost-effectiveness of a telephone-based weight management and healthy lifestyle service for patients with knee osteoarthritis, who are overweight or obese.

Methods

An economic evaluation was undertaken alongside a pragmatic randomised controlled trial. Between May 19 and June 30, 2015, 120 patients with knee osteoarthritis were randomly assigned to an intervention or usual care control group in a 1:1 ratio. Participants in the intervention group received a referral to an existing non-disease specific 6-month telephone-based weight management and healthy lifestyle service. Quality-adjusted life years (QALYs) was the utility measure and knee pain intensity, disability, weight, and body mass index (BMI) were the clinical measures of effect. Costs included intervention costs, healthcare utilisation costs (healthcare services and medication use) and absenteeism costs due to knee pain. Data was collected at baseline, 6?weeks and 26?weeks. The primary cost-effectiveness analysis was performed from the societal perspective.

Results

Mean cost differences between groups (intervention minus control) were $493 (95%CI: -3513 to 5363) for healthcare costs, $-32 (95%CI: -73 to 13) for medication costs, and $125 (95%CI: -151 to 486) for absenteeism costs. The total mean difference in societal costs was $1197 (95%CI: -2887 to 6106). For QALYs and all clinical measures of effect, the probability of the intervention being cost-effective compared with usual care was less than 0.36 at all willingness-to-pay values.

Conclusions

From a societal perspective, telephone-based weight loss support, provided using an existing non-disease specific 6-month weight management and healthy lifestyle service was not cost-effective in comparison with usual care for overweight and obese patients with knee osteoarthritis.

Trial registration number

ACTRN12615000490572, registered 18th May 2015
  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