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   14556篇
  免费   1081篇
  国内免费   51篇
耳鼻咽喉   132篇
儿科学   353篇
妇产科学   325篇
基础医学   2595篇
口腔科学   178篇
临床医学   1548篇
内科学   3052篇
皮肤病学   260篇
神经病学   1012篇
特种医学   564篇
外科学   2212篇
综合类   114篇
现状与发展   1篇
一般理论   2篇
预防医学   910篇
眼科学   237篇
药学   1234篇
中国医学   14篇
肿瘤学   945篇
  2023年   78篇
  2022年   84篇
  2021年   244篇
  2020年   186篇
  2019年   274篇
  2018年   337篇
  2017年   294篇
  2016年   288篇
  2015年   351篇
  2014年   446篇
  2013年   609篇
  2012年   862篇
  2011年   801篇
  2010年   448篇
  2009年   465篇
  2008年   727篇
  2007年   724篇
  2006年   652篇
  2005年   644篇
  2004年   596篇
  2003年   520篇
  2002年   508篇
  2001年   349篇
  2000年   349篇
  1999年   331篇
  1998年   171篇
  1997年   118篇
  1996年   125篇
  1995年   104篇
  1994年   131篇
  1993年   107篇
  1992年   257篇
  1991年   241篇
  1990年   281篇
  1989年   285篇
  1988年   262篇
  1987年   225篇
  1986年   240篇
  1985年   243篇
  1984年   184篇
  1983年   166篇
  1982年   100篇
  1981年   87篇
  1979年   121篇
  1978年   87篇
  1977年   69篇
  1975年   79篇
  1974年   107篇
  1973年   99篇
  1972年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
A dysmorphic child was found by cytogenetic analysis to have an extra small marker chromosome. The marker chromosome was shown to possess a chromosome 18 centromere by in situ hybridization, and probably represents an isochromosome 18p. Centromere specific probes should be of value in identifying extra small marker chromosomes, and thereby provide better understanding of the clinical significance of these.  相似文献   
42.
43.
44.
OBJECTIVES: The transmission of vibrations from the tympanic membrane to the stapes footplate by an ossicular reconstruction prosthesis is affected by the size of the prosthesis head. We sought to determine if augmenting or reducing the head size of prosthesis had a systematic effect on transmission of vibrations to the stapes. STUDY DESIGN: We conducted a fresh cadaveric temporal bone middle ear study. METHODS: The incus was replaced with a prosthesis using a tympanic membrane to stapes head (TASH)-type hydroxyapatite prosthesis in nine fresh cadaveric temporal bones. Three prosthesis head sizes were created: unaltered, reduced, and augmented. Stapes vibrations were measured with a laser Doppler vibrometer in response to acoustic frequency chirps at 90 dB SPL. RESULTS: All three head size prostheses resulted in smaller stapes vibrations than the intact ear. There was no difference in the vibration transmission between the three different head sizes. All prostheses showed a vibration loss of 10 to 15 dB compared to the intact ear. CONCLUSIONS AND SIGNIFICANCE: Within the range of sizes tested, prosthesis head size had little impact on vibration transmission to the stapes footplate.  相似文献   
45.
One hundred ninety patients with peritonitis at the time of abdominal surgery were allocated at random to systemic antibiotic treatment alone or systemic antibiotic treatment combined with topical application of antibiotics in the wound at the time of wound closure. The overall wound infection rate was 17 percent without significant difference between the two treatment groups (P>0.80).  相似文献   
46.
A large series of rabbit hippocampal Neo-Timm stained sections were manually aligned, digitized, and by a modified median filtration noise reduced and reconstructed into a three-dimensional object. From the presented simulated grey tone cuts of this object, the reader may assemble a rabbit hippocampal model, that spatially illustrates its anatomy.  相似文献   
47.
Pinacidil uptake and effects in the isolated rabbit heart   总被引:1,自引:0,他引:1  
The myocardial accumulation of pinacidil showed one-compartment characteristics with a half-time of 1.11 min., whereas the disposition followed three-compartment kinetics with half-times for the relevant two redistributory and the terminal phases of 0.39, 1.51 and 5.44 min., respectively. At a steady-state drug concentration in the perfusate of 6.12 nmol ml-1, the average concentration of pinacidil in the myocardium was 20.6 nmol g-1. The accumulated amount could predictically be referred with 57% to a central and 31 and 12% to two peripheral (deeper) drug pools. The pharmacodynamic effects of pinacidil in the isolated perfused rabbit heart were studied at stepwise increasing concentrations from 0.15 to 100 microM. Coronary flowrate increased initially up to 24.5% at 1.5 microM pinacidil and then gradually decreased. Amplitude and velocity of contraction were both inhibited in a biphasic way up to 92.7 and 94.1%, respectively. Apparent dynamic steady states developed within 13-15 min. The computer-derived inhibitory Em-values related to the first phase were 49.2 and 52.4% and those related to the second phase were 111.7 and 108.3%, respectively. Heart frequency decreased monophasically and exhibited an inhibitory Em-value of 19.6%. Oxygen consumption decreased at pinacidil concentrations higher than 15 microM and the Em-value was 69.7%. The frequency-corrected QT-interval decreased biphasically and the related inhibitory Em-values were 8.6 and 58.7%. The QRS-interval did not change and the PQ-interval only showed a minor increase at the highest pinacidil concentration. Our findings are compatible with the concept of pinacidil being a potassium channel opener.  相似文献   
48.
49.
Tropical pyomyositis, though common in Africa, South America, and the South Pacific, is relatively rare in North America. Reported is the case of a patient who developed chest wall muscle abscesses after sustaining minor chest wall muscle trauma and presented to the emergency department appearing acutely ill. He was treated surgically with irrigation and debridement of the abscesses as well as with antibiotics and recovered fully over a seven-month course. This case illustrates important aspects of tropical pyomyositis with a discussion of the natural history of this disease as well as diagnostic modalities and treatment options for this virulent infectious process that is usually caused by penicillin-resistant Staphylococcus aureus.  相似文献   
50.
Summary The aim of the present study was to compare the ability of different doses of isosorbide-5-mononitrate (5-ISMN) to cause dilatation of medium sized and small arteries, and to examine the intensity and duration of any headache produced. Ten healthy volunteers each received 3 doses of 5-ISMN and placebo on separate days. The diameters of the radial and superficial temporal arteries were repeatedly measured with high frequency ultrasound and pain was scored using a 10 point verbal scale.A clear dose-relationship was found for plasma concentrations and headache, and for changes in the diameter of the temporal artery, but not for the radial artery.It is concluded that headache after 5-ISMN is caused by arterial dilatation or by mechanisms responsible for the arterial dilatation. Ultrasound monitoring of arterial diameters is an important and sensitive tool in the evaluation of nitrates and other vasodilators.  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