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   761篇
  免费   49篇
  国内免费   13篇
耳鼻咽喉   1篇
儿科学   97篇
妇产科学   2篇
基础医学   47篇
口腔科学   17篇
临床医学   77篇
内科学   116篇
皮肤病学   6篇
神经病学   12篇
特种医学   185篇
外科学   79篇
综合类   47篇
预防医学   18篇
眼科学   5篇
药学   36篇
  1篇
肿瘤学   77篇
  2022年   5篇
  2021年   9篇
  2020年   3篇
  2019年   3篇
  2018年   8篇
  2017年   7篇
  2016年   6篇
  2015年   12篇
  2014年   6篇
  2013年   8篇
  2012年   17篇
  2011年   14篇
  2010年   15篇
  2009年   12篇
  2008年   16篇
  2007年   22篇
  2006年   26篇
  2005年   19篇
  2004年   17篇
  2003年   18篇
  2002年   11篇
  2001年   24篇
  2000年   8篇
  1999年   14篇
  1998年   26篇
  1997年   24篇
  1996年   20篇
  1995年   25篇
  1994年   25篇
  1993年   36篇
  1992年   15篇
  1991年   11篇
  1990年   17篇
  1989年   24篇
  1988年   30篇
  1987年   47篇
  1986年   37篇
  1985年   30篇
  1984年   16篇
  1983年   23篇
  1982年   12篇
  1981年   19篇
  1980年   13篇
  1979年   16篇
  1978年   18篇
  1977年   9篇
  1976年   4篇
  1975年   8篇
  1974年   5篇
  1933年   2篇
排序方式: 共有823条查询结果,搜索用时 15 毫秒
751.
Schuening  FG; Storb  R; Stead  RB; Goehle  S; Nash  R; Miller  AD 《Blood》1989,74(1):152-155
Amphotropic helper-free retroviral vectors containing either the bacterial neomycin phosphotransferase gene (NEO) or a mutant dihydrofolate reductase gene (DHFR*) were used to infect canine hematopoietic progenitor cells. In previous experiments, successful transfer and expression of both genes in canine CFU-GM were achieved after 24-hour cocultivation with virus-producing cells. The average rate of gene expression was 10% (6% to 16%) as measured by the number of CFU-GM resistant to either the aminoglycoside G418 or methotrexate. In an attempt to increase the efficiency of gene transfer, marrow was cocultured for 24 hours with either NEO or DHFR* virus-producing packaging cells and then kept in long-term marrow culture fed three times with virus-containing supernatant (2 to 5 x 10(6) CFU/mL). After six days, cells were harvested and cultured in CFU-GM assay with and without a selective agent. The average rate of gene expression in CFU- GM in five independent experiments was 46% and ranged from 19% to 87%. In conclusion, the efficiency of gene transfer into canine hematopoietic progenitor cells has been increased fourfold by combining cocultivation with long-term marrow culture as compared with results obtained with cocultivation only.  相似文献   
752.
753.
754.
SUMMARY: This study aimed to determine treatment preference of various femoral fracture patterns in children by pediatric orthopedists and whether it is practice dependent. In September 1998, members of the Pediatric Orthopedic Society of North America were surveyed to determine their current preferences in treating each of four middle one-third femoral fracture patterns in four age groups. Forty-four percent (286/656) of those surveyed responded. For each fracture pattern, operative treatment was increasingly preferred over nonoperative as patient age increased, and the preferred treatments within the operative and nonoperative categories changed significantly as patient age increased. Fourteen specific cases of femoral head avascular necrosis were noted after rigid reamed and unreamed rodding. There is a statistically significant trend by pediatric orthopedists to treat older children's femur fractures operatively and younger children's nonoperatively. The consensus treatment is age dependent. The numerous cases of avascular necrosis after rigid rodding are a concern.  相似文献   
755.
Pain represents the major motivating factor for which individuals seek healthcare, and pain responses are characterized by substantial inter‐individual differences. Increasing evidence suggests that genetic factors contribute significantly to individual differences in responses to both clinical and experimental pain. The purpose of this review article was to summarize the current literature regarding genetic contributions to pain, highlighting findings relevant to oral pain where available. A brief discussion of methodologic considerations is followed by a review of findings regarding genetic influences on clinical pain. Next, the literature examining genetic contributions to experimental pain responses is presented, emphasizing genetic associations that have been replicated in multiple cohorts. It is hoped that an enhanced understanding of genetic contributions to pain responses will ultimately improve diagnosis and treatment of clinical pain conditions.  相似文献   
756.
Migraine, particularly migraine with aura, and increased body weight are independent risk factors for cardiovascular disease (CVD). The association of weight change and clinical markers of CVD risk was evaluated in subjects participating in a randomized double-blind, parallel-group study of migraine-preventive treatment comparing 100 mg/day of topiramate and amitriptyline. Individuals from both treatment groups were pooled and stratified into three groups. The 'major weight gain' group gained ≥ 5% of their baseline body weight at the conclusion of the study; the 'major weight loss' group lost ≥ 5% of their baseline body weight. The third group had < 5% of weight change. The influence of weight change in headache outcomes, as well as in markers of CVD (blood pressure, cholesterol, C-reactive protein), was assessed using analysis of covariance. Of 331 subjects, 52 (16%) experienced major weight gain and 56 (17%) experienced major weight loss. Weight change was not associated with differential efficacy for the treatment of headache. However, contrasted with those with major weight loss, those who gained weight experienced elevations in mean diastolic blood pressure (+2.5 vs. −1.2 mmHg), heart rate (+7.6 vs. −1.3 beats per minute), glycosylated haemoglobin (+0.09% vs. −0.04%), total cholesterol (+6.4 vs. −6.3 mg/dl), low-density lipoprotein cholesterol (+7.0 vs. −4.4 mg/dl) and triglycerides (+15.3 vs. −10.4 mg/dl) and an increase in high-sensitivity C-reactive protein (+1.8 vs. −1.9 mg/l). Both groups experienced decreases in systolic blood pressure (−4.0 vs. −1.3 mmHg) and high-density lipoprotein cholesterol (−3.7 vs. −0.8 mg/dl). Increased weight during migraine treatment is not associated with poor headache treatment outcomes, but is associated with deterioration of CVD risk markers.  相似文献   
757.
758.
759.
760.
The article deals with endoscopic endonasal transsphenoidal surgery, which has gained great interest among the modem trends of neurosurgery. Application of extended endoscopic endonasal transsphenoidal approaches significantly advances capabilities of transsphenoidal surgery. Pituitary adenomas and some other sellar tumors which traditionally require transcranial procedure now can be removed via endonasal route.  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