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   19053篇
  免费   1219篇
  国内免费   89篇
耳鼻咽喉   174篇
儿科学   518篇
妇产科学   384篇
基础医学   2158篇
口腔科学   341篇
临床医学   1560篇
内科学   4056篇
皮肤病学   237篇
神经病学   1033篇
特种医学   604篇
外科学   3340篇
综合类   699篇
一般理论   17篇
预防医学   1443篇
眼科学   514篇
药学   1851篇
中国医学   219篇
肿瘤学   1213篇
  2024年   69篇
  2023年   172篇
  2022年   520篇
  2021年   657篇
  2020年   431篇
  2019年   531篇
  2018年   643篇
  2017年   446篇
  2016年   368篇
  2015年   515篇
  2014年   699篇
  2013年   876篇
  2012年   1290篇
  2011年   1270篇
  2010年   747篇
  2009年   591篇
  2008年   999篇
  2007年   999篇
  2006年   941篇
  2005年   847篇
  2004年   776篇
  2003年   691篇
  2002年   586篇
  2001年   552篇
  2000年   492篇
  1999年   402篇
  1998年   185篇
  1997年   144篇
  1996年   146篇
  1995年   132篇
  1994年   78篇
  1993年   97篇
  1992年   206篇
  1991年   194篇
  1990年   165篇
  1989年   179篇
  1988年   158篇
  1987年   161篇
  1986年   131篇
  1985年   151篇
  1984年   117篇
  1983年   90篇
  1982年   62篇
  1981年   63篇
  1979年   97篇
  1978年   64篇
  1977年   69篇
  1976年   53篇
  1975年   63篇
  1973年   54篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
81.
54 patients who had posterolateral thoracotomy were prospectively studied to compare the efficacy of intrapleural bupivacaine with that of bupivacaine intercostal block and cryofreezing. Patients were randomized into three groups. The intrapleural catheter group included 16 patients who had intermittent intrapleural instillation of 20 ml of 0.25% bupivacaine for forty-eight hours postoperatively. The second group included sixteen patients who were given perioperative bupivacaine intercostal block. The third group included fifteen patients treated by cryofreezing of the intercostal nerves. Visual analogue four-hourly pain score was compared between the three groups during the first forty-eight hours postoperatively. The analgesic requirements during the first postoperative week were also assessed. There was no significant difference between the three groups in the average pain score (3.61 +/- 1.37, 3.54 +/- 1.15, and 3.33 +/- 1.47 respectively). During the first forty-eight hours postoperatively, the percentage of patients who required papaveretum in the intrapleural catheter group (56.3%) was significantly less than that in the other two groups (both 100%). The average papaveretum requirement (mg per patient) in the intrapleural catheter group (27.33 +/- 25.27) was significantly less than that in the second group (52.66 +/- 26.85) but the difference was not statistically significant from that in the third group (37.66 +/- 20.95). No complications related to the use of the intrapleural catheter or to bupivacaine toxicity were encountered. In conclusion, the technique of intermittent intrapleural bupivacaine is safe and comparable in efficacy to bupivacaine intercostal block and cryofreezing. Narcotic requirements may be reduced when this technique is used.  相似文献   
82.

Background

The maternal, newborn, and child health (MNCH) indicators of Pakistan depict the deplorable state of the poor and rural women and children. Many MNCH programmes stress the need to engage the poor in community spaces. However, caste and class based hierarchies and gendered social norms exclude the lower caste poor women from accessing healthcare. To find pathways for improving the lives of the excluded, this study considers the social system as a whole and describes the mechanisms of exclusion in the externally created formal community spaces and their interaction with the indigenous informal spaces.

Methods

The study used a qualitative case study design to identify the formal and informal community spaces in three purposively selected villages of Thatta, Rajanpur, and Ghizer districts. Community perspectives were gathered by conducting 37 focus group discussions, based on participatory rural appraisal tools, with separate groups of women and men. Relevant documents of six MNCH programmes were reviewed and 25 key informant interviews were conducted with programme staff.

Results

We found that lower caste poor tenants and nomadic peasants were excluded from formal and informal spaces. The formal community spaces formed by MNCH programmes across Pakistan included fixed, small transitory, large transitory, and emerging institutional spaces. Programme guidelines mandated selection of community notables in groups/committees and used criteria that prevented registration of nomadic groups as eligible clients. The selection criteria and adverse attitude of healthcare workers, along with inadequacy of programmatic resources to sustain outreach activities also contributed to exclusion of the lower caste poor women from formal spaces. The informal community spaces were mostly gender segregated. Infrequently, MNCH information trickled down from the better-off to the lower caste poor women through transitory interactions in the informal domestic sphere.

Conclusion

A revision of the purpose and implementation mechanisms for MNCH programmes is mandated to transform formal health spaces into sites of equitable healthcare.
  相似文献   
83.
With the rising prevalence of obesity, hedonic eating has become an important theme in obesity research. Hedonic eating is thought to be that driven by the reward of food consumption and not metabolic need, and this has focused attention on the brain reward system and how its dysregulation may cause overeating and obesity. Here, we begin by examining the brain reward system and the evidence for its dysregulation in human obesity. We then consider the issue of how individuals are able to control their hedonic eating in the present obesogenic environment and compare 2 contrasting perspectives on the control of hedonic eating, specifically, enhanced control of intake via higher cognitive control and loss of control over intake as captured by the food addiction model. We conclude by considering what these perspectives offer in terms of directions for future research and for potential interventions to improve control over food intake at the population and the individual levels.  相似文献   
84.
85.
Endoscopic surgeries have gained popularity not only in ENT but also in other surgical faculties. Endoscopic approach for sinus surgeries and otologic surgeries is well known. However, the major disadvantage of endoscopic aided surgeries as against microscope aided surgeries is thought to be the effective reduction in the working hands as the non-dominant hand of the surgeon is utilized for holding the endoscope. This urged the need for development of the endoscopic holder so as to allow both the hands of the surgeon for surgical manipulation.

Electronic supplementary material

The online version of this article (doi:10.1007/s12070-014-0738-y) contains supplementary material, which is available to authorized users.  相似文献   
86.
87.
88.
Purpose: To highlight that recessive CERKL mutations cause an early-onset rod-cone dystrophy with initially preserved visual acuity despite early macular involvement, an unusual and distinct initial phenotypic presentation.

Methods: A retrospective case series.

Results: Two young Saudi Arabian adults complained of worsening night blindness over the preceding few years, one of whom had been symptomatic since early childhood. Both had retinal pigment epithelium (RPE) mottling/granularity, vascular attenuation, few bone spicules, and frank macular RPE atrophic changes despite relatively preserved visual acuity. Electroretinography was non-recordable, and ocular coherence tomography confirmed retinal thinning, particularly of the outer nuclear layer in the fovea. Each patient harbored a different homozygous CERKL mutation (p.L245P, p.C333*). The few prior reports that detail the presenting phenotype of CERKL mutations describe children or young adults with the similar unusual presenting constellation of findings: rod-cone dystrophy and frank macular atrophy but relatively preserved visual acuity. With time, central vision is affected.

Conclusions: The initial presenting features of CERKL-related retinopathy are distinct and unusual. Recognition of this initial presenting phenotype can facilitate earlier molecular diagnosis and genetic counseling.  相似文献   

89.
Inappropriate initial antibiotics for pneumonia infection are usually linked to extended intensive care unit stay and are associated with an increased risk of mortality. This study evaluates the impact of inappropriate initial antibiotics on the length of intensive care unit stay, risk of mortality and the co-predictors that influences these outcomes. This retrospective study was conducted in an intensive care unit of a teaching hospital. The types of pneumonia investigated were hospital-acquired pneumonia and ventilator-associated pneumonia. Three different time points were defined as the initiation of appropriate antibiotics at 24 h, between 24 to 48 h and at more than 48 h after obtaining a culture. Patients had either hospital-acquired pneumonia (59.1%) or ventilator-associated pneumonia (40.9%). The length of intensive care unit stay ranged from 1 to 52 days (mean; 9.78±10.02 days). Patients who received appropriate antibiotic agent at 24 h had a significantly shorter length of intensive care unit stay (5.62 d, P<0.001). The co-predictors that contributed to an extended intensive care unit stay were the time of availability of susceptibility results and concomitant diseases, namely cancer and sepsis. The only predictor of intensive care unit death was cancer. The results support the need for early appropriate initial antibiotic therapy in hospital-acquired pneumonia and ventilator-associated pneumonia infections.  相似文献   
90.
Recent reports suggest that cimetidine acutely reduces liver blood flow in normal healthy subjects. To determine whether this finding is applicable to critically ill patients, we studied nine polytrauma patients admitted to a surgical ICU. All patients were being monitored with pulmonary artery catheters; all were stable with normal liver function. Liver blood flow was estimated by indocyanine green clearance, before and after administration of a single dose of 600 mg cimetidine. Hemodynamic variables were measured at the same times. Cimetidine did not significantly alter either hepatic blood flow or cardiovascular status in these critically ill patients.  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