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   1369篇
  免费   188篇
  国内免费   18篇
耳鼻咽喉   20篇
儿科学   53篇
妇产科学   20篇
基础医学   87篇
口腔科学   38篇
临床医学   275篇
内科学   292篇
皮肤病学   107篇
神经病学   53篇
特种医学   133篇
外科学   193篇
综合类   94篇
现状与发展   30篇
预防医学   59篇
眼科学   15篇
药学   32篇
中国医学   3篇
肿瘤学   71篇
  2024年   18篇
  2023年   181篇
  2022年   12篇
  2021年   16篇
  2020年   57篇
  2019年   26篇
  2018年   51篇
  2017年   48篇
  2016年   41篇
  2015年   55篇
  2014年   85篇
  2013年   63篇
  2012年   29篇
  2011年   36篇
  2010年   76篇
  2009年   93篇
  2008年   34篇
  2007年   58篇
  2006年   28篇
  2005年   22篇
  2004年   17篇
  2003年   23篇
  2002年   19篇
  2001年   22篇
  2000年   16篇
  1999年   29篇
  1998年   39篇
  1997年   53篇
  1996年   41篇
  1995年   36篇
  1994年   29篇
  1993年   34篇
  1992年   10篇
  1991年   9篇
  1990年   11篇
  1989年   24篇
  1988年   21篇
  1987年   17篇
  1986年   4篇
  1985年   14篇
  1984年   5篇
  1983年   3篇
  1982年   8篇
  1981年   10篇
  1980年   13篇
  1978年   5篇
  1977年   3篇
  1976年   13篇
  1975年   10篇
  1974年   3篇
排序方式: 共有1575条查询结果,搜索用时 15 毫秒
81.
Aim: To investigate mothers’ perceptions of breastfeeding and influences from their social network. Methods: A cross‐sectional survey was carried out in Mangochi district, Malawi where questionnaire data from 157 rural and 192 semi‐urban mother–infant pairs were obtained. Results: The proportion of mothers who thought that exclusive breastfeeding should last for 6 months and those who reported to have actually exclusively breastfed were 40.1% and 7.5% respectively. Of those who reported practising exclusive breastfeeding for 6 months, 77.5% stated that exclusive breastfeeding should last for 6 months. This opinion was independently associated with giving birth in a Baby‐Friendly facility, OR = 5.22; 95% CI (1.92–14.16). Among the mothers who thought that exclusive breastfeeding should last for less than 6 months, 43.9% reported having been influenced in their opinion by health workers. Infant crying was the most common (62.4%) reason for stopping exclusive breastfeeding. Conclusion: The findings illustrate the positive impact health workers can have, as well as the need to raise awareness of the benefits of exclusive breastfeeding among both health workers and mothers. Furthermore, continued counselling of mothers on how to deal with stressful infant behaviour such as crying may assist to prolong exclusive breastfeeding.  相似文献   
82.
83.
84.
Background: Impaired intestinal mucosal barrier (IMB) function is common in traumatic brain injury (TBI), but dopamine receptors (DRs) change in intestinal mucosa after TBI, and effects of enteral nutrition (EN) and supplements on IMB function remain unclear. Our purpose was to study the effects of EN and supplements on intestinal mucosal permeability (IMPB) and the expression of DRs DRD1 and DRD2 in the intestinal mucosa of rats with TBI. Methods: Forty‐eight rats were divided into 8 groups; control, animals with TBI, dopamine group, animals with TBI treated with dopamine antagonist, EN alone, or EN combined with glutamine, probiotics, or a combination of probiotics and glutamine daily after TBI. Results: The IMPB was improved in the glutamine, probiotics, and combination groups. Including probiotics improved IMPB more than adding glutamine, and bacterial translocation in the intestines after TBI was reduced in the probiotics and combination groups (all Ps < .01). TBI led to elevated DRD1 and DRD2 mRNA and protein levels, which were reduced in the DA antagonist, glutamine, probiotics, and combination groups. DRD2 mRNA and protein levels in the probiotics and combination groups were decreased more than in the DA antagonist group (all Ps < .01). The increased IMPB after TBI correlated with increased DRD1 and DRD2 levels in the rat intestinal mucosa. Conclusion: EN supplemented with probiotics or combining glutamine and probiotics lowers the increased IMPB, bacterial translocation, and DRD1 and DRD2 mRNA and protein expression in rat intestinal mucosa caused by TBI.  相似文献   
85.

Background  

Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting.  相似文献   
86.

Background  

Diabetes prevalence is increasing. The Finnish Diabetes Prevention Study (DPS) showed a 58% reduction in Type 2 Diabetes (T2D) incidence in adults with impaired glucose tolerance (IGT). The European Diabetes Prevention Study (EDIPS) extends the DPS to different European populations, using the same study design. In the Newcastle arm of this study (EDIPS-Newcastle), we tested the hypothesis that T2D can be prevented by lifestyle intervention and explored secondary outcomes in relation to diabetes incidence.  相似文献   
87.

Background  

Accurate measurement of physical activity is a pre-requisite for monitoring population health and for evaluating effective interventions. The International Physical Activity Questionnaire (IPAQ) is used as a comparable and standardised self-report measure of habitual physical activity of populations from different countries and socio-cultural contexts. The IPAQ has been modified to produce a New Zealand physical activity questionnaire (NZPAQ). The aim of this study was to validate the IPAQ and NZPAQ against doubly labelled water (DLW). Method: Total energy expenditure (TEE) was measured over a 15-day period using DLW. Activity-related energy expenditure (AEE) was estimated by subtracting the energy expenditure from resting metabolic rate and thermic effect of feeding from TEE. The IPAQ (long form) and NZPAQ (short form) were completed at the end of each 7-day period. Activity-related energy expenditure (IPAQAEE and NZPAQAEE) was calculated from each questionnaire and compared to DLWAEE.  相似文献   
88.

Background

Immunological response of host and parasite play a key role in developing vaccination and immunization. The present study deals with the immune response and effecter mechanism, which was confirmed by migration inhibition factor (MIF).

Methods

The present work was conducted in Parasitological Lab of Postgraduate Department of Zoology, Government Holkar Science College, Indore (M.P.) during 2006–2007. For MIF assay, lymphocytes were separated from heparinized blood of experimental and control mice. Aliquots of cell suspension were placed in four wells cut in a preparation of agarose in a Petri dish. Two wells were filled with soluble test antigen, while rest two wells were filled with medium (control wells). Petri dish was incubated overnight at 37 °C in a humidified environment at 5% CO2 in air. Cells migrated under the agarose in a circle were fixed and stained. Diameters of the migration areas were measured with ocular micrometer.

Results

MIF reaction was maximum (44.2%) in the group IVEgESAg5 and minimum (10.8%) in the group IVASoAg1. The maximum MIF reaction was shown by eggs ES antigen and least by adult worm somatic antigen. The interesting observation was that migration inhibition increases as dose increased or we could say the reaction was dose dependent.

Conclusion

Increased value of MIF response in vaccinated mice suggested the involvement of lymphocytes in cell-mediated immunity. This study also proves that excretory-secretory (ES) antigen of eggs from Trichuris muris was more effective in imparting immunity in mice.  相似文献   
89.

Background

Neospora caninum, an obligate intracellular protozoan parasite, is recognized as a major cause of abortion in cattle, while limited information is presently available on the seroprevalence of Neospora antibodies in horses’ worldwide. The aim of the present study was to determine serologic prevalence of Neospora infection in horses in Iran.

Methods

Sera from 150 horses from Mashhad suburb in Razavi Khorasan Province, northeast Iran were examined for antibodies to Neospora spp. using Neospora modified direct agglutination test (N-MAT).

Results

Antibodies to this parasite were detected in 45 (30%) of the examined serum samples. Thirty four percent of the samples had titer of 1:40 while then reduced to 30% when 1:80 serum dilution was applied as significant cut off titer.

Conclusion

This study is the first investigation carried out on the Neospora in horses in Iran and indicates that horses in Iran are exposed to this parasite.  相似文献   
90.
Hepatitis B virus (HBV) reactivation is a remarkable risk during the chemotherapy for solid tumour patients. Nucleos(t)ide analogues (NAs) are recommended as prophylaxis for the reactivation of HBV infection in some cancer patients prior to systemic chemotherapy. Therefore, we performed a meta‐analysis aiming to determine the efficacy of prophylactic lamivudine on prevention of HBV reactivation and its related negative outcomes among solid tumour patients with chronic HBV infection receiving systemic chemotherapy. The primary outcome was HBV reactivation, and the secondary outcomes were HBV‐related hepatitis, chemotherapy disruption, mortality and tyrosine‐methio‐nine‐aspartate‐aspartate (YMDD) mutations. Twelve original researches involving 1,101 patients were analysed in this study. The relative risk of HBV reactivation in patients with lamivudine prophylaxis was significantly lower than that without prophylaxis (RR = 0.17, 95% CL: 0.10‐0.29, < .00001). Lamivudine prophylaxis reduced the relative risk of hepatitis (p < .00001), chemotherapy disruptions (p = .01) and mortality (p = .08) due to HBV reactivation. Lamivudine prophylaxis is effective in reducing HBV reactivation and its related negative outcomes, such as hepatitis and chemotherapy disruption and mortality among chemotherapeutic solid tumour patients with chronic HBV infection. Future studies should lay more emphasis on the early HBV screening, mode of treatment and duration of NAs prophylaxis among solid tumour patients receiving chemotherapy.  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