全文获取类型
收费全文 | 56281篇 |
免费 | 3433篇 |
国内免费 | 1566篇 |
专业分类
耳鼻咽喉 | 389篇 |
儿科学 | 970篇 |
妇产科学 | 690篇 |
基础医学 | 4586篇 |
口腔科学 | 1053篇 |
临床医学 | 5285篇 |
内科学 | 5835篇 |
皮肤病学 | 470篇 |
神经病学 | 3136篇 |
特种医学 | 1324篇 |
外国民族医学 | 6篇 |
外科学 | 5807篇 |
综合类 | 10643篇 |
现状与发展 | 1篇 |
一般理论 | 4篇 |
预防医学 | 5428篇 |
眼科学 | 943篇 |
药学 | 4820篇 |
118篇 | |
中国医学 | 8009篇 |
肿瘤学 | 1763篇 |
出版年
2024年 | 207篇 |
2023年 | 989篇 |
2022年 | 1776篇 |
2021年 | 2369篇 |
2020年 | 2178篇 |
2019年 | 2275篇 |
2018年 | 1953篇 |
2017年 | 1835篇 |
2016年 | 1717篇 |
2015年 | 1499篇 |
2014年 | 3548篇 |
2013年 | 3179篇 |
2012年 | 3148篇 |
2011年 | 3948篇 |
2010年 | 3586篇 |
2009年 | 2648篇 |
2008年 | 2442篇 |
2007年 | 2647篇 |
2006年 | 2451篇 |
2005年 | 2025篇 |
2004年 | 1638篇 |
2003年 | 1541篇 |
2002年 | 1056篇 |
2001年 | 943篇 |
2000年 | 771篇 |
1999年 | 711篇 |
1998年 | 557篇 |
1997年 | 528篇 |
1996年 | 422篇 |
1995年 | 472篇 |
1994年 | 435篇 |
1993年 | 333篇 |
1992年 | 331篇 |
1991年 | 296篇 |
1990年 | 252篇 |
1989年 | 251篇 |
1988年 | 251篇 |
1987年 | 210篇 |
1986年 | 206篇 |
1985年 | 425篇 |
1984年 | 417篇 |
1983年 | 331篇 |
1982年 | 368篇 |
1981年 | 355篇 |
1980年 | 343篇 |
1979年 | 305篇 |
1978年 | 274篇 |
1977年 | 245篇 |
1976年 | 183篇 |
1975年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
本研究主要对El Tor型霍乱弧菌(Vibrio cholerae biotvpe eltor,EVC)L型的某些生物学特性如生化反应、抗生素敏感性及超微结构等进行了探讨.研究发现EVC不稳定L型的生化性状与EVC流行株的非常相似,而稳定L型则变化很大.抗生素敏感性试验显示EVC稳定L型对某些作用于细胞壁的抗生素的敏感性减弱,而对大多数作用于蛋白质合成的抗生素的敏感性增强.与流行株相比,EVC稳定L型和不稳定L型的超微结构的改变很明显.此外,本文还讨论了产生这些改变的可能机制. 相似文献
62.
63.
O. D. Golenko E. E. Batrak M. F. Kharchenko 《Bulletin of experimental biology and medicine》1998,125(3):282-285
Inhibitory effect of glycosaminoglycans isolated from peripheral blood granulocytes of patients with chronic myeloleukemia
and normal subjects on increment in colony-forming units of fibroblasts in monolayer cultures of rat bone marrow is determined
by the degree of sulfation of their main component chondroitin-4-sulfate and by increased content of heparan sulfate.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 3, pp. 319–322, March, 1998 相似文献
64.
Kurtis W. Andrews David A. Savitz Irva Hertz-Picciotto 《American journal of industrial medicine》1994,26(1):13-32
Although the adverse effect on pregnancy outcomes at high levels of lead exposure in the workplace has been recognized for years, there is uncertainty regarding the impact of exposure at the lower community exposure levels commonly encountered today. This review summarizes the epidemiologic literature and discusses pertinent methodologic issues and possible sources of interstudy variation. The authors conclude that prenatal lead exposure is unlikely to increase the risk of premature membrane rupture but does appear to increase the risk of preterm delivery. Whether prenatal lead exposure decreases gestational age in terms of infants is unclear. Prenatal lead exposure also appears to be associated with reduced birth weight, but results vary in relation to study design and degree of control for confounding. Adjustment for gestational age, a possible confounder of the birth weight-lead exposure association, did not yield clearer results. 相似文献
65.
We present a patient with vertebrobasilar insufficiency, with vertigo and horizontal nystagmus, induced by turning the head to the right. Angiography demonstrated transient occlusion of the left vertebral artery at the atlantoaxial joint during rotation of the head. The pathogenesis and angiographic findings are discussed. 相似文献
66.
本文采用俯卧拍背法缓解胆绞痛41例,其中23例经此法治疗后疼痛立即消失(56.1%);15例明显缓解(36.6%);3例缓解不明显(7.3%)。具有操作简便、安全,易被患者接受,值得推广。 相似文献
67.
We report a newly developed MR simulation system for intracavitary brachytherapy for cervical cancer and subsequent treatment results. MR simulation was performed on six patients. The spatial relationship of the tumor to the bladder, rectum, bowel, applicators, etc. was depicted well. Doses to the tumor and surrounding normal tissues were read from isodose curves superimposed on the T2-weighted sagittal image. This system promises to be useful in customizing the dose distribution. 相似文献
68.
By a double-labeling method combining the retrograde tracing of horseradish peroxidase and the immunocytochemical technique, serotonin-like immunoreactive neurons in the midbrain periaqueductal gray (PAG) and nucleus raphe dorsalis (DR) of the rat were observed to send projection fibers to the nucleus parafascicularis of the thalamus bilaterally with an ipsilateral dominance. These serotonin-containing projecting neurons were observed mainly at the middle-caudal levels of the ventrolateral subdivision of the PAG and less at the middle-rostral levels of the DR. 相似文献
69.
70.
Six numerical integration algorithms based on linear and log trapezoidal methods as well as four cubic-spline methods were proposed for estimation of area under the curve (AUC). These six different algorithms were implemented using IMSL/IDLTM command language and evaluated using data simulated under five different dosing conditions and two different sampling conditions. Comparisons between AUC estimations using these six different algorithms and the theoretical results were made in terms of both overall AUC values and the superimposability of the concentration-time profiles. In well designed studies with ample data points, the algorithm based on IMSL/IDLTM function CSSHAPE with concavity preservation gave the best performance. In contrast, when the frequency of blood collection was limited, the algorithm based on the log trapezoidal rule proved to be stable with reasonable accuracy, and is recommended as the practical method for numerical interpolation and integration in pharmacokinetic studies. Algorithms based on the combination of the log trapezoidal rule and cubic-spline methods using IMSL/IDLTM function CSSHAPE can be developed to enhance overall performance. 相似文献