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   62037篇
  免费   5703篇
  国内免费   3503篇
耳鼻咽喉   512篇
儿科学   920篇
妇产科学   1018篇
基础医学   7085篇
口腔科学   1093篇
临床医学   7258篇
内科学   10099篇
皮肤病学   767篇
神经病学   2938篇
特种医学   2780篇
外国民族医学   34篇
外科学   7379篇
综合类   9092篇
现状与发展   15篇
一般理论   16篇
预防医学   4005篇
眼科学   1507篇
药学   6561篇
  53篇
中国医学   3082篇
肿瘤学   5029篇
  2024年   177篇
  2023年   848篇
  2022年   2081篇
  2021年   2867篇
  2020年   2071篇
  2019年   1897篇
  2018年   2038篇
  2017年   1810篇
  2016年   1805篇
  2015年   2505篇
  2014年   3170篇
  2013年   3186篇
  2012年   4460篇
  2011年   4737篇
  2010年   3097篇
  2009年   2561篇
  2008年   3377篇
  2007年   3467篇
  2006年   3191篇
  2005年   2978篇
  2004年   2400篇
  2003年   2218篇
  2002年   2014篇
  2001年   1685篇
  2000年   1616篇
  1999年   1448篇
  1998年   856篇
  1997年   850篇
  1996年   688篇
  1995年   581篇
  1994年   506篇
  1993年   357篇
  1992年   527篇
  1991年   427篇
  1990年   410篇
  1989年   379篇
  1988年   308篇
  1987年   286篇
  1986年   227篇
  1985年   182篇
  1984年   135篇
  1983年   95篇
  1982年   77篇
  1981年   82篇
  1980年   52篇
  1979年   77篇
  1978年   43篇
  1977年   43篇
  1976年   41篇
  1972年   42篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
纤维支气管镜胸膜腔检查对原因不明胸腔积液的诊断价值   总被引:2,自引:0,他引:2  
为评价纤维支所管镜行胸膜检查在诊断原因不明胸腔积液中的价值,用纤维支气管镜对10例原因不明的胸腔积液患者进行胸腔检查。结果9例2检查后明确了病因,且无并发症,提示该法对于不明胸腔积液的诊断是一种阳性率高、安全、简便的检查方法。  相似文献   
32.
卡介苗激活杀伤细胞抗膀胱肿瘤作用研究   总被引:1,自引:0,他引:1  
为了进一步探讨BCG抗膀胱肿瘤的作用机理,采取15例膀胱肿瘤患者外周血单个核细胞(PBMC),置于含BCG或IL2的培养基中培养,计算扩增倍数,检测培养细胞抗自体及异体膀胱癌细胞活性。结果:卡介苗激活杀伤细胞(BAK)与淋巴因子激活杀伤细胞(LAK)分别于培养第7和第3天达增殖高峰,对自体瘤杀伤率分别为36.2%和31.4%,差异有显著性(P<0.05);对异体瘤杀伤率分别为25.2%和28.3%,差异无显著性。结果表明:BAK细胞抗自体瘤活性高于LAK细胞,死BCG对PBMC无激活作用,BAK细胞抗肿瘤效应可能是BCG抗膀胱肿瘤重要作用机理之一。  相似文献   
33.
Twenty-one patients, under 6 years of age, with root avulsion of the brachial plexus were treated from 1975 to 1987. Among them, 9 had root avulsion of the upper trunk, 2 root avulsion of the lower trunk with middle trunk broken, and 10 root avulsion of the whole brachial plexus. Follow-up of 16 patients showed excellent results in 2 patients, good in 11, fair in 1 and poor in 2. It is suggested that good results can be obtained if multi-paired nerve transfer is adopted in treatment. We conclude that owing to anatomical and physiological characteristics of the respiratory system in children, it is harmful to perform phrenic nerve transfer concomitantly with intercostal nerve transfer. Advisably, two-stage operation is required, otherwise dyspnea and pneumonia are liable to occur. In addition, the time of the operation could be extended to 4-5 years after injury in children, but best results are obtained if the operation is performed within 1 year.
  相似文献   
34.
1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.  相似文献   
35.
MK-679 (R(?)-3-((3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)(3-(dimethylamino)-3-oxopropyl)thio)methyl)thio(propanoic acid) is a potent and specific LTD4-receptor antagonist. The disposition of MK-679 was investigated in a three-way crossover study in 12 healthy males receiving single intravenous doses of 75, 250, and 500 mg of MK-679. A greater than proportional increase in the area under the plasma concentration—time curve of MK-679 was observed with increase in dose. The plasma concentration data for each subject fitted well to the differential equations for a two-compartment model with linear tissue distribution and Michaelis-Menten elimination from the central compartment, indicating that the elimination of MK-679 in humans is saturable. In a previous study, the disposition of MK-679 in humans was also dose-dependent when given together with its S(+)-isomer, L-668,018. Thus, the disposition of MK-679 in humans is dose-dependent regardless of the presence of its stereoisomer. Also, the bioavailability of MK-679 was determined in six healthy males receiving simultaneously an oral dose of 250 mg of MK-679 and intravenous infusion of 1 mg 14C-MK-679. Results of this study indicate that the oral bioavailability of MK-679 is nearly quantitative.  相似文献   
36.
孙琼  俞锡林 《营养学报》1992,14(3):266-269
本文对14岁以下健康小儿171名,成人30名及初生儿脐带血30份进行了血清叶酸和维生素B_(12)含量测定,171名小儿于采血前均经补足叶酸和维生素B_(12)。结果:血清叶酸(nmol/L)的正常值低限,<4岁者为6.1,4~14岁为8.4,成人为5.0;血清维生素B_(12)(pmol/L)的正常值低限,<1岁为459,1岁~成人为107。  相似文献   
37.
W C Cheng  A D Wang 《Neurosurgery》1990,27(5):802-805
Carotid-cavernous sinus fistulas are not rare, but they have never been reported in association with persistent primitive trigeminal artery. We recently encountered such a case. The Jaeger-Hamby procedure was employed, with mandatory occlusion of the primitive trigeminal artery.  相似文献   
38.
光镜和电镜观察慢性宫颈炎上皮不典型增生42例,宫颈癌21例,正常对照7例。上皮不典型增生之一是位于深部的储备细胞增生,细胞的核质比大,细胞器少,分化较低。鳞状上皮不典型增生细胞特点是核质比增大,核形不整,核膜内陷,细胞器增多,桥粒和张力原纤维减少。鳞癌细胞的核质比更大,核膜内褶深,细胞器更多,桥粒和张力原纤维很少或消失,分化低的癌细胞尤明显。粘液性腺癌腺上皮深部可见储备细胞转化的癌细胞。  相似文献   
39.
脊髓手术中体感诱发电位监测的临床研究   总被引:3,自引:0,他引:3  
报告30例脊髓手术中体感诱发电位(SEP)连续监测的临床研究结果。SEP记录包括脊髓SEP(SSEP)和皮层SEP(SCEP)。麻醉药物对SEP有一定程度影响,SCEP相对较大。认为,至少术中SEP潜伏期延长不超过8%和波幅降低不超过50%,不会引起术后并发症,超过该范围由于病例较少,尚不能肯定与预后的关系,需进一步探讨。  相似文献   
40.
应用PcR法提高了淋球菌阳性检出率并与培养法做比较。118例拟诊淋病患者的样本采自尿道分泌物或宫颈分泌物,部分采自前段尿。用双盲法测定,结果检出率分别为73.7%和49.1%,PcR法的阳性检出率明显高于培养法,P<0.05。总阳性符合率分别为92.7%和69.8%,PcR法显著高于培养法P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