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   1740篇
  免费   67篇
  国内免费   3篇
耳鼻咽喉   10篇
儿科学   55篇
妇产科学   38篇
基础医学   117篇
口腔科学   58篇
临床医学   390篇
内科学   526篇
皮肤病学   51篇
神经病学   47篇
特种医学   11篇
外科学   147篇
综合类   30篇
一般理论   18篇
预防医学   122篇
眼科学   19篇
药学   146篇
中国医学   3篇
肿瘤学   22篇
  2017年   18篇
  2016年   21篇
  2015年   26篇
  2014年   33篇
  2013年   46篇
  2012年   10篇
  2010年   51篇
  2009年   60篇
  2008年   12篇
  2007年   12篇
  2006年   17篇
  2005年   11篇
  2003年   12篇
  2001年   25篇
  2000年   14篇
  1999年   45篇
  1998年   62篇
  1997年   92篇
  1996年   95篇
  1995年   60篇
  1994年   59篇
  1993年   67篇
  1992年   51篇
  1991年   56篇
  1990年   49篇
  1989年   56篇
  1988年   53篇
  1987年   40篇
  1986年   32篇
  1985年   30篇
  1984年   41篇
  1983年   38篇
  1982年   26篇
  1981年   35篇
  1980年   23篇
  1979年   16篇
  1978年   16篇
  1977年   18篇
  1976年   13篇
  1975年   11篇
  1971年   20篇
  1968年   11篇
  1959年   20篇
  1958年   32篇
  1957年   32篇
  1956年   38篇
  1955年   31篇
  1954年   26篇
  1949年   11篇
  1948年   12篇
排序方式: 共有1810条查询结果,搜索用时 0 毫秒
1.
2.
Collagenous colitis is characterized by the presence of a thick subepithelial collagen band in the colonic mucosa. The condition was diagnosed on rectal biopsy in 10 patients (one male, nine females) who presented with watery diarrhoea. Although rectal mucosal erythema was present in three and ulceration in two, the mucosa was of normal endoscopic appearance in five of the patients. There was marked variability in the thickness of the submucosal collagen band, both between and within individuals. Empirical drug therapy included sulphasalazine, glucocorticoids and antidiarrhoeals. All patients reported symptomatic improvement.  相似文献   
3.
4.
Preventing accidental injury to young children in the home using volunteers   总被引:1,自引:0,他引:1  
Accidental injury in the home is a major cause of death andill-health among young children. Reducing home safety hazardsby the use of safety devices such as stair barriers and safetytaps has the potential to prevent home injuries. Little is knownabout levels of home safety hazards or how to encourage parentsto reduce hazards. The Safe Place Project examined parents'knowledge of home safety and the prevalence of safety hazardsin homes where there were young children. The study also evaluatedthe effectiveness of a low-cost strategy aimed at reducing homesafety hazards. The strategy used trained volunteers to providehome safety checks and tailored safety education in conjunctionwith increasing the availability of home safety devices. Onehundred and six families with young children participated inthe project. Some homes contained many hazards, with 43% ofthe sample having more than 10 home safety hazards. At follow-up,the intervention group showed a significant reduction in homehazards and a trend towards an increase in knowledge of homesafety.  相似文献   
5.
The 5-year “Preventing Alcohol Trauma: A Community Trial” project in the United States was designed to reduce alcohol-involved injuries and death in three experimental communities. The project consisted of five mutually reinforcing components: (1) Community Mobilization Component to develop community organization and support, (2) Responsible Beverage Service Component to establish standards for servers and owner/managers of on-premise alcohol outlets to reduce their risk of having intoxicated and/or underage customers in bars and restaurants, (3) Drinking and Driving Component to increase local DWI enforcement efficiency and to increase the actual and perceived risk that drinking drivers would be detected, (4) Underage Drinking Component to reduce retail availability of alcohol to minors, and (5) Alcohol Access Component to use local zoning powers and other municipal controls of outlet number and density to reduce the availability of alcohol. This paper gives an overview of the rationale and causal model, the research design and outline of each intervention component for the entire prevention trial.  相似文献   
6.
In order to evaluate the effects of pentoxifylline on sperm motility and longevity, a controlled in-vitro study was conducted on normozoospermic donor semen samples using the Cellsoft automated system for sperm motility analysis. After incubation and selection, pentoxifylline was found to improve the recovery of spermatozoa and to increase their velocity. In the subgroup of progressively motile spermatozoa, curvilinear velocity was also enhanced. It is concluded that pentoxifylline has an effect on the vigour, but not on the pattern, of sperm motion. Pentoxifylline did not improve the motility characteristics of senescent spermatozoa in normozoospermic sperm samples. Sperm survival, as shown by supra-vital staining, and motility longevity both decreased with time after pentoxifylline treatment.  相似文献   
7.
The analogues [Glu(OBzl)11]SP6–11 and [Glu(OBzl)11]SP5–11 of the C-terminal hexapeptide and heptapeptide of Substance P have been synthesized by conventional solution methods. In each analogue the SCH3 group of Met11 is replaced by the COOCH2C6H5 group. The in vitro activity of both analogues has been determined on three biological preparations: guinea pig ileum (GPI), rat vas deferens (RVD), and rat portal vein (RPV). The selectivity for the different receptors has been studied by utilizing atropine-treated guinea pig ileum (GPI + At). The results showed that both analogues are mainly active on GPI through the NK-1 receptor and that both analogues are equipotent to Substance P.  相似文献   
8.
Dialytic ultrafiltration with haemofilter was performed in 16 patients with malignant ascites refractory to treatment with sodium restriction, diuretic and systemic chemotherapy. A continuous flow of ascitic fluid at a rate of 300–400 ml/min through a haemofilter was maintained by a blood pump. The protein-rich ascitic fluid was re-infused into the peritoneal cavity with sodium and water removed. An average of 5.2 1 of filtrate was removed over a mean interval of 3.5 h. Bleomycin (60 mg) was administered intraperitoneally following the procedure. Complete response was observed in six patients (37.25%) and partial response occurred in four (25%). The remaining patients showed no response. Complications of the dialytic ultrafiltration procedure and toxicity of intraperitoneal administration of bleomycin were minimal. The technique of dialytic ultrafiltration is simple, safe and cost-effective and could be used as an adjuvant therapy for intraperitoneal chemotherapy.  相似文献   
9.
The current treatment of choice for chronic tympanic membrane perforations is surgery. Recent studies using various polypeptide growth factors to accelerate closure of tympanic membrane perforations in model systems have produced mixed results. This study evaluates the effect of acidic fibroblast growth factor (AFGF) and live yeast cell derivative (LYCD) on the rate of healing of acute tympanic membrane perforations in a rat model. Thirty-seven rats had both ears separately randomized in a blinded fashion to receive AFGF in one of three concentrations, LYCD, or a control solution. The rats initially underwent subtotal removal of the tympanic membranes bilaterally. Solutions were applied to the randomized ears daily for 3 days, starting at the time of the surgical perforation. The ears were photographed every 3 to 8 days for 35 days. The photographs were digitally scanned and a computer analysis was used to calculate the percentage of residual perforation. No significant difference in the rate of healing was observed for ears treated with AFGF or LYCD versus the controls. Given the potential advantages of medical treatment of tympanic membrane perforations and the established efficacy of growth factors in other model systems, however, further research is warranted. (Otolaryngol Head Neck Surg 1997;117:616-21.)  相似文献   
10.
Thirty-eight from a total of 42 known HIV-positive prisoners in the Irish prison system voluntarily cooperated in a survey of psychological attitudes, knowledge of risk behaviour, intentions with respect to future risk behaviour, and actual past risk behaviour Of this group, 65% reported that they had put others at risk of HIV, since they became aware of their own HIV + status. Only 16% stated that they would definitely not share their drug-taking equipment in the future and 32% that they would always use a condom in sexual intercourse. In general, psychological and biographical variables were not strongly related to whether or not the respondents had put others at risk of HIV. Nor were there any significant differences in knowledge of at risk behaviour between those who had and those who had not put others at risk. However, there was some evidence for considerable independence between risk-taking behaviour in the sexual and in the drug-taking domains, in that risk-taking in one area was not highly predictive of risk-taking in the other.  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