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   24787篇
  免费   2439篇
  国内免费   494篇
耳鼻咽喉   197篇
儿科学   381篇
妇产科学   1498篇
基础医学   2426篇
口腔科学   450篇
临床医学   3156篇
内科学   2870篇
皮肤病学   173篇
神经病学   1805篇
特种医学   1516篇
外国民族医学   4篇
外科学   1949篇
综合类   3214篇
现状与发展   1篇
一般理论   3篇
预防医学   2802篇
眼科学   437篇
药学   2734篇
  50篇
中国医学   1077篇
肿瘤学   977篇
  2024年   85篇
  2023年   425篇
  2022年   723篇
  2021年   1092篇
  2020年   1075篇
  2019年   1005篇
  2018年   1058篇
  2017年   1041篇
  2016年   945篇
  2015年   984篇
  2014年   1702篇
  2013年   1832篇
  2012年   1442篇
  2011年   1572篇
  2010年   1330篇
  2009年   1153篇
  2008年   1117篇
  2007年   1126篇
  2006年   1079篇
  2005年   812篇
  2004年   764篇
  2003年   642篇
  2002年   578篇
  2001年   395篇
  2000年   359篇
  1999年   341篇
  1998年   262篇
  1997年   223篇
  1996年   207篇
  1995年   196篇
  1994年   201篇
  1993年   146篇
  1992年   151篇
  1991年   149篇
  1990年   154篇
  1989年   137篇
  1988年   131篇
  1987年   109篇
  1986年   102篇
  1985年   130篇
  1984年   120篇
  1983年   109篇
  1982年   86篇
  1981年   101篇
  1980年   83篇
  1979年   50篇
  1978年   36篇
  1977年   34篇
  1976年   36篇
  1973年   20篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
BACKGROUND: Consistent evidence has indicated that air pollution increases the risk of cardiovascular diseases. The underlying mechanisms linking air pollutants to increased cardiovascular risk are unclear. OBJECTIVES: We investigated the association between the pollution levels and changes in such global coagulation tests as the prothrombin time (PT) and the activated partial thromboplastin time (APTT) in 1218 normal subjects from the Lombardia Region, Italy. Plasma fibrinogen and naturally occurring anticoagulant proteins were also evaluated. METHODS: Hourly concentrations of particulate (PM10) and gaseous pollutants (CO, NO2, SO2, and O3) were obtained from 53 monitoring sites covering the study area. Generalized additive models were applied to compute standardized regression coefficients controlled for age, gender, body mass index, smoking, alcohol, hormone use, temperature, day of the year, and long-term trends. RESULTS: The PT became shorter with higher ambient air concentrations at the time of the study of PM10 (coefficient = -0.06; P < 0.05), CO (coefficient = -0.11; P < 0.001) and NO2 (coefficient =-0.06; P < 0.05). In the 30 days before blood sampling, the PT was also negatively associated with the average PM(10) (coefficient = -0.08; P < 0.05) and NO2 (coefficient = -0.08; P < 0.05). No association was found between the APTT and air pollutant levels. In addition, no consistent relations with air pollution were found for fibrinogen, antithrombin, protein C and protein S. CONCLUSIONS: This investigation shows that air pollution is associated with changes in the global coagulation function, suggesting a tendency towards hypercoagulability after short-term exposure to air pollution. Whether these changes contribute to trigger cardiovascular events remains to be established.  相似文献   
72.
目的 分析分娩期子宫破裂的发病原因及预防措施。方法 回顾分析1985年8月至2001年12月,16a间64例分娩期子宫破裂的临床资料。结果 子宫收缩剂使用不当3l例,占48.4%;胎先露下降受阻13例,占20.3%;子宫疤痕16例,占25%;阴道助产4例,占6.3%。初产妇10例(10.9%);经产妇54例(89.1%)。结论 降低分娩期子宫破裂发生率关键在于加强计划生育工作及围生期保健,严格掌握子宫收缩剂的适应证及剂量;严格首次剖宫产指征;严密观察产程,及时处理异常分娩。  相似文献   
73.
74.
非霍奇金淋巴瘤85例临床及预后分析   总被引:3,自引:0,他引:3  
目的:分析多种因素对非霍奇金淋巴瘤(NHL)预后的影响。方法:通过SABC法进行免疫分型,采用Kaplan—Meier法分析患者治疗后的生存期,采用Cox比例风险模型分析影响预后的因素。结果:B细胞来源-NHL(B-NHL)发病率为63.3%。T细胞来源-NHL(T—NHL)为36.7%;低度恶性占17.6%,中、高度恶性占74.1%。1、2、3、5年生存率:低度恶性患者为92.1%、84.5%、65.1%、45.1%;中、高度恶性患者为84.9%、67.5%、47.6%、28.4%。I、Ⅱ期患者为98.8%、91.5%、87.5%、70.3%;Ⅲ期、Ⅳ期患者为62.1%、55.5%、40.1%、23.8%。T—NHL为70.8%、53.5%、47.7%、30.2%;B-NHL为82.1%、70.5%、61.1%、50.1%。结论:年龄、乳酸脱氢酶水平、恶性程度、临床分期、免疫分型、身体状况评分(PS)是影响NHL预后的重要因素。  相似文献   
75.
Among British-qualified doctors of 1974 and 1977, about 80% held postgraduate qualifications of some kind. The commonest qualifications were DRCOG, MRCP and MRCOG. There were considerable differences between medical schools in the numbers of qualifiers taking various examinations. Apart from the MRC Psych, DRCOG and Family Planning Certificate, qualifications were more commonly held by men than women. Tables show the type of work being done 9-13 years after leaving medical school by holders of various postgraduate qualifications; e.g. 60% of MRCP holders were working in medicine or a medical specialty and 84% of FRCS holders in general surgery or a surgical specialty. Discussion deals with the plurality, specificity, variability, perceived necessity, sufficiency, international utility and career significance of British postgraduate qualifications.  相似文献   
76.
护士执业权是依法取得护士执业证书,以护士名义为社会提供护理服务的医务人员进行护理工作的权利和相关权益,是护士执业规则的核心内容,护士执业权属于公民劳动权益的范畴,是一种具有职业特权性质的特殊劳动权,应立法保护。本文试图通过对护士执业权的法理初步探讨,结合目前存在的侵害护士执业权的突出现象分析,提出保护该项权利的立法建议。  相似文献   
77.
TUVP手术时间对血红蛋白及电解质的影响   总被引:2,自引:0,他引:2  
目的 了解经尿道前列腺汽化电切手术时间对血红蛋白及血清电解质的影响。方法 对64例经尿道前列腺汽化电切术患按手术时间分组,观察手术前后血红蛋白及血清电解质的变化。结果 手术时间对血清电解质的降低有的影响,对血红蛋白降低的影响不显。结论 减少TUR综合征的关键是要操作熟练,缩短手术时间及手术中注意止血。  相似文献   
78.
A method has been derived for calculating the mean absorption time of an oral drug and its interconversion metabolite which is generated from the drug systemically and presystemically. The method evolves from the convolution integral and requires plasma AUC and AUMC values after separate intravenous administration of the drug and its interconversion metabolite and oral administration of the drug. It can also be used to calculate the mean input time of a drug undergoing reversible metabolism and administered by any other extravascular route. Results of a simulation study using both errorless and errant data indicate that, when the absorption rate constant of a drug or its interconversion metabolite is not much larger than the apparent elimination rate constant, the proposed method performs satisfactorily. However, when the absorption rate constant of a drug or its interconversion metabolite is much larger than the apparent elimination rate constant, the proposed method appears to be inaccurate.  相似文献   
79.
Little is known about whether patients with photosensitive disorders exhibit a different ultraviolet erythema time course from subjects with a normal response to sunlight. We have described the application of an instrument for ambulatory monitoring of the development of ultraviolet erythema by a reflectance method in a group of patients with chronic actinic dermatitis (CAD) and in a group of normal subjects. Investigations of the time course have been reported previously but the techniques used relied upon manual measurement. Consequently sampling frequencies have been considerably lower than the one-minute sample rate used here. We have not demonstrated any difference in the rate at which erythema develops and peaks between patients with CAD and subjects with a normal response to sunlight.  相似文献   
80.
报告本院1981年1月至1985年12月,住院分娩4588例中产后并发症341例,发病率为7.43%。其中,产后出血1189例,占4.12%;分娩损伤71例,占1.55%;其它产后病81例,占1.76%。妊娠41—42周并发症发生率为11.14%;超过42周高达15.56%。分娩方式以剖腹产术后并发症最多,占12.48%,提示应对手术中无菌操作与环境,以及分娩后处理应予以足够重视。  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