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   1841篇
  免费   180篇
  国内免费   8篇
耳鼻咽喉   18篇
儿科学   101篇
妇产科学   38篇
基础医学   240篇
口腔科学   67篇
临床医学   215篇
内科学   361篇
皮肤病学   26篇
神经病学   133篇
特种医学   149篇
外科学   249篇
综合类   75篇
预防医学   151篇
眼科学   40篇
药学   65篇
中国医学   1篇
肿瘤学   100篇
  2022年   15篇
  2021年   40篇
  2020年   23篇
  2019年   47篇
  2018年   71篇
  2017年   43篇
  2016年   50篇
  2015年   53篇
  2014年   60篇
  2013年   98篇
  2012年   80篇
  2011年   57篇
  2010年   76篇
  2009年   78篇
  2008年   49篇
  2007年   80篇
  2006年   57篇
  2005年   71篇
  2004年   38篇
  2003年   51篇
  2002年   32篇
  2001年   38篇
  2000年   29篇
  1999年   35篇
  1998年   54篇
  1997年   50篇
  1996年   54篇
  1995年   51篇
  1994年   26篇
  1993年   37篇
  1992年   23篇
  1991年   21篇
  1990年   17篇
  1989年   34篇
  1988年   28篇
  1987年   27篇
  1986年   30篇
  1985年   28篇
  1984年   18篇
  1983年   29篇
  1982年   12篇
  1981年   22篇
  1980年   15篇
  1979年   18篇
  1978年   12篇
  1977年   20篇
  1976年   16篇
  1975年   14篇
  1973年   18篇
  1972年   16篇
排序方式: 共有2029条查询结果,搜索用时 31 毫秒
71.
72.
Objectives. We tested the efficacy of a sexual risk-reduction intervention for men in South Africa, where heterosexual exposure is the main mode of HIV transmission.Methods. Matched-pairs of neighborhoods in Eastern Cape Province, South Africa, were randomly selected and within pairs randomized to 1 of 2 interventions based on social cognitive theory and qualitative research: HIV/sexually transmitted infection (STI) risk-reduction, targeting condom use, or attention-matched control, targeting health issues unrelated to sexual risks. Sexually active men aged 18 to 45 years were eligible. The primary outcome was consistent condom use in the past 3 months.Results. Of 1181 participants, 1106 (93.6%) completed the 12-month follow-up. HIV and STI risk-reduction participants had higher odds of reporting consistent condom use (odds ratio [OR] = 1.32; 95% confidence interval [CI] = 1.03, 1.71) and condom use at last vaginal intercourse (OR = 1.40; 95% CI = 1.08, 1.82) than did attention-control participants, adjusting for baseline prevalence. No differences were observed on unprotected intercourse or multiple partnerships. Findings did not differ for sex with steady as opposed to casual partners.Conclusions. Behavioral interventions specifically targeting men can contribute to efforts to reduce sexual risk behaviors in South Africa.South Africa has more HIV cases than any other country, and like other sub-Saharan countries, has a predominantly heterosexual epidemic.1 In such an epidemic, men have an especially critical role to play: they are the ones who don male condoms, a particularly effective and available means of prevention, and thus control their use. They have, it has been argued, more power than women in relationships2–4 and are responsible for infecting women in many contexts, including forced intercourse and violence.3 Although calls for male responsibility in sexual behavior related to HIV and other sexually transmitted infections (STIs) have been made repeatedly,5–7 to our knowledge, only 1 study has evaluated an intervention created specifically for heterosexual men in South Africa.8 Men who received the gender-based-violence-and-HIV-risk-reduction intervention were more likely to report talking with a partner about condoms and using condoms consistently 1-month postintervention compared with men in an alcohol-and-HIV-risk-reduction control intervention.The present study evaluated an HIV/sexually transmitted infection (STI) risk-reduction intervention for South African men who have intercourse with women. We used a cluster-randomized design to reduce the potential for contamination between treatment arms that would be present if we were to randomize individuals. We randomized randomly selected neighborhoods (i.e., clusters) to a 3-session intervention based on social cognitive theory9 and extensive formative research10 and designed to reduce HIV/STI risk behavior or to a 3-session attention-control intervention designed to promote health by improving diet and physical activity. We hypothesized that the HIV/STI risk-reduction intervention would increase self-reported consistent condom use during vaginal intercourse in the postintervention period, the primary outcome, compared with the attention-control intervention, controlling for baseline condom use.  相似文献   
73.

Objective

Group B Streptococcus (GBS) causes significant infant morbidity and mortality. Promising GBS vaccines are currently in clinical trials. Because GBS vaccines would be the first to specifically target pregnant women, we sought to assess acceptability of a hypothetical GBS vaccine.

Study design

We performed an internet survey among currently pregnant or recently delivered women receiving care at one of 9 Ob/Gyn practices in Colorado. Vaccine acceptability was assessed using questions based on constructs from the Health Belief Model. Multivariable analyses assessed the characteristics associated with GBS vaccine acceptability during the current/recent pregnancy.

Results

The response rate was 50% (n = 231). While 78% agreed that a GBS vaccine would be a good way to protect newborns, 90% and 83% agreed, respectively, that they worried generally about the safety and effectiveness of new vaccines. Moreover, 39% believed it is generally dangerous for pregnant women to get vaccines. Seventy nine percent ‘definitely’ or ‘probably’ would have gotten a GBS vaccine in their most recent pregnancy if available. The most influential factors associated with this outcome were a strong belief in the vaccine's benefits (adjusted odds ratio [AOR] 6.37, 95% confidence interval [CI] 2.01–20.16), and low perceived barriers to vaccination (AOR 0.11, 95% CI (0.03–0.37)).

Conclusion

A GBS vaccine may be acceptable to pregnant women but would benefit from strong provider support and education about the risks and consequences of GBS infection and the benefits to vaccination.  相似文献   
74.
The present study evaluated the importance of multimodal assessment of childhood verbal abuse (CVA) in pre-bariatric surgery psychological evaluations, and the role of CVA as a predictor of depression. Data from the psychological evaluations of 184 pre-bariatric surgery patients were retrospectively examined. Using two self-report measures and an interview-based screen, 52.2 % of participants reported experiencing some form of CVA; conversely, assessments of CVA based on only one measure yielded significantly lower prevalence rates. Endorsement of CVA on multiple measures was associated with more severe depressive symptomatology and greater likelihood of mood disorder diagnosis. Based on these data, a self-report measure and interview-based screen for CVA should be included in pre-bariatric psychological evaluations; either of these assessments may be conducted via a single-item screen. Lastly, patients who endorse CVA on multiple measures should be monitored closely for symptoms of depression post-surgery.  相似文献   
75.

Background

In the Netherlands, screening for chlamydia (the most prevalent sexually transmitted infection worldwide) is a relatively simple and free procedure. Via an invitation letter sent by the public health services (PHS), people are asked to visit a website to request a test kit. They can then do a chlamydia test at home, send it anonymously to a laboratory, and, within two weeks, they can review their test results online and be treated by their general practitioner or the PHS. Unfortunately, the participation rates are low and the process is believed to be not (cost-) effective.

Objective

The objective of this study was to assess whether the low participation rate of screening for chlamydia at home, via an invitation letter asking to visit a website and request a test kit, could be improved by optimizing the invitation letter through systematically applied behavior change theories and evidence.

Methods

The original letter and a revised letter were randomly sent out to 13,551 citizens, 16 to 29 years old, in a Dutch municipality. Using behavior change theories, the revised letter sought to increase motivation to conduct chlamydia screening tests. The revised letter was tailored to beliefs that were found in earlier studies: risk perception, advantages and disadvantages (attitude), moral norm, social influence, and response- and self-efficacy. Revisions to the new letter also sought to avoid possible unwanted resistance caused when people feel pressured, and included prompts to trigger the desired behavior.

Results

No significant differences in test package requests were found between the two letters. There were also no differences between the original and revised letters in the rates of returned tests (11.80%, 581/4922 vs 11.07%, 549/4961) or positive test results (4.8%, 23/484 vs 4.1%, 19/460). It is evident that the new letter did not improve participation compared to the original letter.

Conclusions

It is clear that the approach of inviting the target population through a letter does not lead to higher participation rates for chlamydia screening. Other approaches have to be developed and pilot tested.  相似文献   
76.
77.
78.
A fascinating yet perhaps overlooked trait of the p75 neurotrophin receptor (p75NTR) is its ability to bind ligands with no obvious neurotrophic function. Using cultured basal forebrain (BF) neurons, this study demonstrates selective internalization of amyloid β (Aβ) 1–42 in conjunction with p75NTR (labelled with IgG192-Cy3) by cholinergic cells. Active under resting conditions, this process was enhanced by high K+ stimulation and was insensitive to inhibitors of regulated synaptic activity—tetrodotoxin or botulinum neurotoxins (BoNT type/A and/B). Blockade of sarco-endoplasmic reticulum (SERCA) Ca2+ ATPase with thapsigargin and CPA or chelation of Ca2+ with EGTA-AM strongly suppressed the endocytosis of p75NTR, implicating the role of ER released Ca2+. The uptake of IgG192-Cy3 was also reduced by T-type Ca2+ channel blocker mibefradil but not Cd2+, an indiscriminate blocker of high voltage-activated Ca2+ currents. A strong co-localization of IgG192-Cy3 with late endosome (Rab7) or lysosome (Lamp1) qualifier proteins suggest these compartments as the primary destination for internalized IgG192 and Aβ. Selective uptake and labeling of BF cholinergic cells with IgG192-Cy3 injected into the prefrontal cortex was verified also in vivo. The significance of these findings in relation to Aβ clearance in the cerebral cortex and pathophysiology of Alzheimer’s disease is discussed.  相似文献   
79.
80.
由于治疗方法的进步,近80%的儿童和青少年癌症患者能够长期生存。在美国,约有270000例儿童癌症的幸存者,即每640名20至39岁成年人中就有一名幸存者。大量的幸存者有利于儿童癌症治疗后长期健康结果的研究。现在可以明确的是,化疗和放疗所致的儿童各器官系统损害在临床上可能潜伏多年。为了全面了解治疗儿童癌症而继发的健康问题,重要的是衡量三项长期结果:健康状况、死亡率和患病率。这三项中,关于前两项已有相当好的研究报道。在一项对20227例癌症5年生存者的回顾性分析中,Mertens等发现以下原因导致的超额死亡率具有统计学意义:继发癌症(…  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