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   165191篇
  免费   6372篇
  国内免费   359篇
耳鼻咽喉   2201篇
儿科学   4771篇
妇产科学   3816篇
基础医学   23705篇
口腔科学   5437篇
临床医学   9378篇
内科学   36548篇
皮肤病学   4559篇
神经病学   13259篇
特种医学   4015篇
外国民族医学   1篇
外科学   19073篇
综合类   828篇
一般理论   24篇
预防医学   19728篇
眼科学   4360篇
药学   12924篇
中国医学   679篇
肿瘤学   6616篇
  2023年   834篇
  2021年   2488篇
  2020年   1399篇
  2019年   2859篇
  2018年   5003篇
  2017年   3111篇
  2016年   3105篇
  2015年   3451篇
  2014年   3786篇
  2013年   5798篇
  2012年   10121篇
  2011年   10687篇
  2010年   5269篇
  2009年   3822篇
  2008年   8743篇
  2007年   9416篇
  2006年   9033篇
  2005年   8647篇
  2004年   8014篇
  2003年   7498篇
  2002年   7129篇
  2001年   4899篇
  2000年   5488篇
  1999年   4173篇
  1998年   714篇
  1992年   2250篇
  1991年   2004篇
  1990年   1999篇
  1989年   1698篇
  1988年   1623篇
  1987年   1530篇
  1986年   1560篇
  1985年   1464篇
  1984年   1046篇
  1983年   900篇
  1979年   1223篇
  1978年   812篇
  1977年   782篇
  1976年   750篇
  1975年   884篇
  1974年   1129篇
  1973年   1177篇
  1972年   1124篇
  1971年   1081篇
  1970年   1019篇
  1969年   1088篇
  1968年   1115篇
  1967年   982篇
  1966年   881篇
  1965年   551篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
53.
A total of 186 blood samples from 24 HIV-1 seropositive hemophiliac patients, monitored every four months for 29 months, were investigated for the presence of viral antigen in plasma. In addition, peripheral blood mononuclear cells (PBMC) were cultured for HIV-1, using normal PBMC as a target for replication. Antigenemia was detected in 51 % of the patients and from PBMC in 87.5 % of the patients. The incidence of HIV isolation in asymptomatic patients (42.8 %) was similar to that found in symptomatic patients (51.4 %). Patients with opportunistic infections had a higher incidence of lymphocytic viremia (p<0.05). Plasma viremia was closely associated (p<0.05) with low CD4+ counts and infection progression. The persistence of antigenemia was also a marker of a poor clinical course. In treated patients, plasma viremia was the marker that better correlated with the clinical course, and it did not appear during the first nine months of therapy. Zidovudine doses of >500 mg/day significantly lowered the appearance of antigenemia and lymphocytic viremia (p<0.05).  相似文献   
54.
A series of N-(phosphonoacetyl)-dipeptide derivatives was synthesized for pharmacological testing as antihypertensive compounds. Several of these compounds demonstrated a moderate antihypertensive effect in Wistar spontaneous hypertensive rats (SHR) with p.o. dosing. ACE inhibition by the compounds was studied using ACE from rat plasma and lung. Inhibitors containing esterified C-termini are pro-drugs and showed activity only for plasma ACE.  相似文献   
55.
Authors describe a case of isolated posttraumatic neuropraxy of the musculocutaneous nerve. With the presentation of this very rare case attention is called, based on literary date, to the fact that the above injury can be mixed with the distal tendon rupture of the biceps.  相似文献   
56.
57.
This research presents reports of cases where a biocompatible and alloplastic biomaterial—Bioplastique—was used, associated with conventional plastic surgery or as a complement to it, with the aim of achieving a better final aesthetic result. Four cases are presented where Bioplastique was used in association with rhytidoplasty, rhinoplasty, and other surgical techniques. This material has shown itself to be appropriate to complement surgery; achieving a final result which would not be possible without any resort to a complement or any other hard procedure by the surgeon and is not more traumatic for the patient.  相似文献   
58.
A study of 52 middle-aged males with essential hypertension, unaccompanied by cardiovascular disorders, is reported. The patients were divided into 2 groups with respect to the type of treatment they received: 30 patients on beta-adrenoblockers and 22 patients on methyldopa. The patients were treated continuously for 2 years under one-dimensional echocardiographic control. The greatest drop in arterial blood pressure and ventricular septum thickness was seen within the first 6 months of treatment, while posterior-wall hypertrophy disappeared altogether. Although there was no further drop in blood pressure after 6 months, the thickness of the ventricular septum remained reduced for at least 2 years. Regression of left-ventricular hypertrophy was not accompanied with any deterioration of left-ventricular performance, nor was it related to additional use of vasodilators.  相似文献   
59.
60.
In order to study the possible regressive changes of left ventricular hypertrophy in treated hypertensive patients and to correlate them either with the drugs they received and/or the blood pressure reduction obtained, a long-term (6 years) echocardiographic follow-up study was performed in 61 patients. B and M mode echocardiographic septum and posterior wall thickness and left ventricular mass index were measured yearly and the type of ventricular hypertrophy, asymmetric septal or concentric (symmetric), were compared before and after the follow-up. Sixteen patients received only diuretics; 14, only propranolol, and associated therapy was used in the remaining 31 patients. Average blood pressure was significantly reduced in the whole group of patients, but, individually, 30 of them achieved normal levels for the diastolic (90 mmHg), remaining it over this value in the other, although all of them experienced an average reduction 10 mmHg with therapy. Those patients with concentric hypertrophy at entry showed a significant septal, posterior wall thickness and total ventricular mass reduction during the follow-up, those with initial asymmetric septal hypertrophy, a significant septal thickness and ventricular mass reduction, and those without hypertrophy on admission, showed an average paradoxical increase in septal thickness. We conclude that left ventricular hypertrophy disappeared or decreased in 48% of the patients and that treatment seems to prevent its progression or development in the 43% of all patients. The regressive or favorable changes were significantly more frequent among patients with normal blood pressure after treatment as well as among patients treated only with propranolol in comparison to those treated only with diuretics.  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