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   17396篇
  免费   1707篇
  国内免费   363篇
耳鼻咽喉   131篇
儿科学   336篇
妇产科学   222篇
基础医学   1278篇
口腔科学   408篇
临床医学   2498篇
内科学   2505篇
皮肤病学   256篇
神经病学   859篇
特种医学   1025篇
外国民族医学   2篇
外科学   1279篇
综合类   3030篇
一般理论   2篇
预防医学   2365篇
眼科学   293篇
药学   1317篇
  106篇
中国医学   556篇
肿瘤学   998篇
  2024年   40篇
  2023年   436篇
  2022年   660篇
  2021年   1114篇
  2020年   1153篇
  2019年   807篇
  2018年   750篇
  2017年   805篇
  2016年   877篇
  2015年   776篇
  2014年   1466篇
  2013年   1390篇
  2012年   1055篇
  2011年   1025篇
  2010年   757篇
  2009年   684篇
  2008年   631篇
  2007年   675篇
  2006年   545篇
  2005年   495篇
  2004年   387篇
  2003年   340篇
  2002年   302篇
  2001年   304篇
  2000年   226篇
  1999年   157篇
  1998年   193篇
  1997年   161篇
  1996年   123篇
  1995年   134篇
  1994年   121篇
  1993年   110篇
  1992年   93篇
  1991年   68篇
  1990年   76篇
  1989年   64篇
  1988年   73篇
  1987年   49篇
  1986年   58篇
  1985年   59篇
  1984年   36篇
  1983年   26篇
  1982年   33篇
  1981年   22篇
  1980年   22篇
  1979年   12篇
  1978年   15篇
  1976年   15篇
  1975年   10篇
  1974年   16篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
81.
取乙型肝炎患者Delta抗体(抗—HD)阳性血清,经硫酸铵盐析和DE—52柱层析,得到纯化的抗—HD抗体,用辣根过氧化物酶标记。用丁型肝炎病毒(HDV)感染慢性携带土拨鼠肝炎病毒的东方土拨鼠(Woodchuck)后,取其肝组织制成匀浆,离心后经Sepharose 4B柱,免疫亲和层析柱,获得高丰度的HDAg。双抗体夹心法测定其滴度高达1∶10~6。制备成ELISA竞争抑制法检测抗HD试剂盒,其特异性、敏感性、重复性与爱尔兰同种试剂比较结果一致。  相似文献   
82.
AnAnalysisofChromosomeonSterilityCausedbyAzoospermiaorOligospermia¥WuMeiheng;TangWingnuo.(ACTAACADEMIAEMEDICINAENANJING,1995(...  相似文献   
83.
通过福田4500型B超软故障检修与分析,介绍了该机故障检修分析过程及造成该故障的原因。  相似文献   
84.
Summary Twenty-two persons (20 men and 2 women) were examined for their external and internal exposure to the glycol ether 1-methoxypropan-2-ol (PGME) during the production, leak testing and mounting of brake-hoses. For the measurement of external exposure, personal air monitoring was the method of choice. Average concentrations of PGME of 82.2 mg/m3 (22.3 ppm), 68.6 mg/m3 (18.6 ppm) and 11.3 mg/m3 (3.1 ppm) were found in the air of the brakehose production, leak test and mounting areas, respectively. For the estimation of internal exposure to PGME, this glycol ether was measured in both urine and blood. The biological samples were taken post-shift. The highest internal exposure levels were found in the brakehose production section and in the leak test area. The average post-shift concentrations for PGME in workers in the brakehose production section were 4.6 mg/l in urine and 13.5 mg/l in blood; the corresponding figures for workers in the leak test area were 4.2 mg/l in urine and 11.0 mg/l in blood. In blood and urine samples of workers engaged in the mounting area, PGME levels were below the detection limits. The elimination kinetics of PGME were also studied in three highly exposed persons, and mean excretion half-lives of PGME of approximately 4.4 h were found. On the basis of our results we made a rough calculation of a future biological tolerance value: we would except that concentrations of 38-109 mg per litre of blood and 10–31 mg per litre of urine would correspond to the German MAK value for PGME (375 mg/m3).  相似文献   
85.
86.
本文对52例晚期产后出血病例进行了分析,结果认为晚期产后出血与感染密切有关;在处理上诊断性刮宫仍是重要措施之一,并提出对存在感染因素的产妇,术前、产前应用抗菌素预防感染.在剖宫产过程中,可用含抗生素的溶液冲洗宫腔,以达到预防感染的目的。  相似文献   
87.
The chest x-ray has become a standard clinical test to aid in the evaluation of patients with chronic severe heart failure. To evaluate just how useful this tool is in the routine assessment of pulmonary venous hypertension secondary to heart failure, we compared the radiologist's interpretation of the chest x-ray with hemodynamic data obtained from right heart catheterization in a group of patients undergoing protocol evaluation of an experimental treatment for heart failure. Of 23 patients with pulmonary venous hypertension (pulmonary capillary wedge pressure greater than 20 mmHg) and a complete data base, only 11 had chest x-rays showing evidence of pulmonary venous congestion or interstitial or alveolar edema. The sensitivity of the chest x-ray in selecting patients with a pulmonary capillary wedge pressure over 20 mmHg in this setting was only 48%. In other studies, where the radiologist was aware that his or her reading was being compared to hemodynamic assessments, the sensitivity of the chest film has approached 85%. We feel our analysis more closely parallels routine clinical practice. Clinicians should be aware that the chest x-ray may not be a very sensitive tool for the assessment of pulmonary hemodynamics in patients with severe heart failure.  相似文献   
88.
AIMS: To estimate the prevalence of diabetes mellitus with three diagnostic criteria (WHO-1985 and 1999 and ADA-1997), evaluate their concordance and analyse the sensitivity and specificity of the different screening strategies for diabetes. METHODS: A cross-sectional population study with two-step sampling. One thousand and 34 people were selected randomly. A 75-g oral glucose tolerance test (OGTT) was performed and venous blood samples were obtained fasting and at 2 h. RESULTS: The prevalence of known Type 2 diabetes mellitus (DM-2) is 4%[95% confidence interval (CI) 2.8, 5.1]. By WHO-1985 criteria the prevalence of unknown DM-2 is 5.9% (4.5, 7.4); by ADA-1997 criteria 3.5% (2.5, 4.6) and by WHO-1999 criteria 7.3% (5.8, 8.8). Diagnostic overlap and statistical concordance (coefficient K) are WHO-1985/ADA-1997 29.3%, K=0.42; WHO-1985/WHO-1999 80%, K=0.88; ADA-1997/WHO-1999 48%, K=0.63. If only fasting glucose was used (following ADA-1997), 36.3% of those with diabetes (2-h glucose > or =11.1 mmol/l) would be diagnosed. If OGTT was performed (i) in those with a fasting glucose between 6.1 mmol/l and 6.9 mmol/l (9.8% of the population) we would diagnose 66.6%, and (ii) in all those between 5.7 mmol/l and 6.9 mmol/l (18.9% of the population) 81.8% would be diagnosed. CONCLUSIONS: The ADA criteria decrease the prevalence of DM in the adult population of Asturias by 2.4% and concordance with the classical criteria (WHO-1985) was only 29.3%. Using fasting glucose only (ADA-1997) diagnoses 36.3% of those with diabetes. The recent recommendations of the WHO-1999 increases this to 66.6%. To improve the diagnostic strategy for diabetes and detect up to 81.8% of patients, we propose the use of OGTT for all those with a fasting glucose between 5.7 mmol/l and 6.9 mmol/l.  相似文献   
89.
本文采用脑电分频积分定量法测定甜菜碱对清醒家兔脑电的影响。清醒家兔静注甜菜碱250mg/kg后,出现高幅幔波夹杂低幅快波脑电,自发脑电积分值((?)vs)显著提高。动物安静少动。结果表明甜菜碱有中枢抑制作用。  相似文献   
90.
应用ELISA测定了54例类风湿性关节炎患者、99例非类风湿性关节炎患者以及100例正常人的血清Ⅱ型胶原抗体,结果阳性率分别为90.7%、0、0.54例类风湿性关节炎患者中有7例血清类风湿因子为阴性而Ⅱ型胶原抗体为阳性,且病程均在半年之内。结果表明:Ⅱ型胶原抗体的检测对类风湿性关节炎具有特异性诊断和早期诊断的临床意义。  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