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   211163篇
  免费   2937篇
  国内免费   147篇
耳鼻咽喉   1630篇
儿科学   7492篇
妇产科学   3705篇
基础医学   21088篇
口腔科学   3691篇
临床医学   14889篇
内科学   40095篇
皮肤病学   1588篇
神经病学   19351篇
特种医学   9623篇
外科学   34068篇
综合类   2527篇
一般理论   13篇
预防医学   20696篇
眼科学   3387篇
药学   11417篇
中国医学   758篇
肿瘤学   18229篇
  2023年   238篇
  2022年   515篇
  2021年   1402篇
  2020年   743篇
  2019年   1103篇
  2018年   22993篇
  2017年   18037篇
  2016年   20255篇
  2015年   1933篇
  2014年   2340篇
  2013年   2630篇
  2012年   9982篇
  2011年   24011篇
  2010年   20481篇
  2009年   12961篇
  2008年   21903篇
  2007年   24126篇
  2006年   3034篇
  2005年   4572篇
  2004年   5402篇
  2003年   6158篇
  2002年   4116篇
  2001年   442篇
  2000年   534篇
  1999年   370篇
  1998年   479篇
  1997年   419篇
  1996年   283篇
  1995年   284篇
  1994年   238篇
  1993年   165篇
  1992年   138篇
  1991年   166篇
  1990年   172篇
  1989年   112篇
  1988年   96篇
  1987年   79篇
  1986年   65篇
  1985年   80篇
  1984年   73篇
  1983年   74篇
  1982年   67篇
  1981年   50篇
  1980年   101篇
  1978年   44篇
  1977年   48篇
  1974年   39篇
  1938年   60篇
  1932年   56篇
  1930年   46篇
排序方式: 共有10000条查询结果,搜索用时 625 毫秒
41.
42.
Using 3,3'-diclorophenolsulfoftaleinil N-acetyl-beta-D-glucosaminide as a substrate, the apparent activation energy of beta-N-acetylhexosaminidase (Hex) was determined in samples of plasma and urine, as well as in leukocyte and platelet lysates. Incubation with papain produced an increase in this thermodynamic variable for plasma Hex (precursor forms with high molecular mass) that would be caused by the proteolytic action of papain on the Hex A isoenzyme. However, digestion with papain did not significantly modify the activation energy of Hex in leukocyte and platelet lysates (mature enzymatic forms). In 11 healthy subjects and 28 patients with different renal diseases, no statistically significant differences were found with regard to the values obtained in cellular lysates for variations in the activation energy of urinary Hex, regardless of whether they presented normoalbuminuria, microalbuminuria or macroalbuminuria. These results support the hypothesis that even in patients with proteinuria, no significant amounts of plasma Hex precursor forms are found in urine samples, and the source of the enzyme activity is the kidney itself.  相似文献   
43.
Anliegen dieses Artikels ist, die besondere Qualit?t und Chance von Psychodramatischer Supervision zu beschreiben, und gleichzeitig die Kompatibilit?t und fruchtbare Erg?nzung des Moreno’schen Ansatzes innerhalb des Formats Supervision innerhalb der Sozialen Arbeit auf zuzeigen. Dies wird anhand von 2 ausgew?hlten Praxisbeispielen dargestellt. Die Handlungskompetenz von Supervisandinnen und Supervisanden kann durch einfache psychodramatische Interventionen erweitert werden. Handlungshemmung wird überwunden, Spontaneit?t und Kreativit?t kommen ins Laufen und er?ffnen Perspektiven.  相似文献   
44.
45.
Relationship-centered care reflects both knowing and feeling: the knowledge that physician and patient bring from their respective domains of expertise, and the physician’s and patient’s experience, expression, and perception of emotions during the medical encounter. These processes are conveyed and reciprocated in the care process through verbal and nonverbal communication. We suggest that the emotional context of care is especially related to nonverbal communication and that emotion-related communication skills, including sending and receiving nonverbal messages and emotional self-awareness, are critical elements of high-quality care. Although nonverbal behavior has received far less study than other care processes, the current review argues that it holds significance for the therapeutic relationship and influences important outcomes including satisfaction, adherence, and clinical outcomes of care.  相似文献   
46.
Uniparental isodisomy (iUPD) is a rare genetic condition caused by non-disjunction during meiosis that ultimately leads to a duplication of either the maternal or paternal chromosome in the affected individual. Two types of disorders can result, those due to imprinted genes and those due to homozygosity of recessive disease-causing mutations. Here, we describe the third known case of complete chromosome 4 iUPD of maternal origin. This condition became apparent during whole genome linkage studies of psychiatric disorders in the Portuguese population. The proband is an adult female with normal fertility and no major medical complaints, but a history of major depressive disorder and multiple suicide attempts. The proband's siblings and parents had normal chromosome 4 genotypes and no history of mood disturbance. A brief review of other studies lends support for the possibility that genes on chromosome 4 might confer risk for mood disorders. We conclude that chromosome 4 maternal uniparental disomy (UPD) is a rare disorder that may present with a major depressive phenotype. The lack of a common disease phenotype between this and two other cases of chromosome 4 iUPD [Lindenbaum et al. [1991] Am J Med Genet 49(Suppl 285):1582; Spena et al. [2004] Eur J Hum Genet 12:891-898) would suggest that there is no vital maternal gene imprinting on chromosome 4. However, since there is no reported case of paternal chromosome 4 UPD, paternal gene imprinting on chromosome 4 cannot be excluded.  相似文献   
47.
INTRODUCTION: Transesophageal echocardiography (TEE) has become increasingly useful in the study of patients with suspected pulmonary thromboembolism. OBJECTIVE: The aim of this study was to prospectively evaluate the usefulness of TEE in the study of the distal part of the left pulmonary artery (LPA) as well as the influence of this procedure on total echocardiographic exam duration. METHODOLOGY: A prospective study in two groups of consecutive patients referred for TEE with a one- year interval between evaluation of Group A: 33 patients, 17 male, mean age 54 +/- 24 years, and Group B: 42 patients, 20 male, mean age 48 +/- 27 years (p = NS). The procedure was considered long when it took more than 3 min to evaluate the distal part of the LPA. RESULTS: In group A we were able to visualize the distal part of the LPA in 24 patients (73%) without significant prolongation of total exam duration in 16 patients (48% of group A). In one of the patients with suspected pulmonary thromboembolism thrombi were only observed in the distal part of the LPA. In group B we were able to visualize the distal part of the LPA in 36 patients (86%) without significant prolongation of total exam duration in 26 patients (61% of group B). CONCLUSIONS: 1. Visualization of the distal part of the LPA was possible in more patients, and with TEE time prolongation in less patients, in group B. These differences can be accounted for by the training of the operator in this technique. 2. The importance of visualization of this part of the LPA in guiding treatment in the subset of patients with pulmonary thromboembolism confirms the usefulness of this specific procedure.  相似文献   
48.
Coronary flow reserve (CFR) has been used toassess coronary microcirculation and epicardial coro-nary stenoses[1— 3 ] . CFR is defined as the ratio ofcoronary flow under maximal coronary vasodilatationto coronary flow under resting conditions[4 ] .Whenthe cross- sectional area of epicardial coronary arteriesis constant,coronary flow velocity (CFV) ratios areequal to volume flow ratios.The most common method used clinically formeasuring CFVR is intracoronary Doppler flow(ICD) analysis re…  相似文献   
49.
50.
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