全文获取类型
收费全文 | 111989篇 |
免费 | 7234篇 |
国内免费 | 447篇 |
专业分类
耳鼻咽喉 | 1204篇 |
儿科学 | 2927篇 |
妇产科学 | 2098篇 |
基础医学 | 13947篇 |
口腔科学 | 2094篇 |
临床医学 | 11951篇 |
内科学 | 22328篇 |
皮肤病学 | 1714篇 |
神经病学 | 11041篇 |
特种医学 | 4279篇 |
外国民族医学 | 3篇 |
外科学 | 18010篇 |
综合类 | 1355篇 |
一般理论 | 143篇 |
预防医学 | 9500篇 |
眼科学 | 2264篇 |
药学 | 7310篇 |
中国医学 | 115篇 |
肿瘤学 | 7387篇 |
出版年
2023年 | 616篇 |
2022年 | 988篇 |
2021年 | 2281篇 |
2020年 | 1427篇 |
2019年 | 2250篇 |
2018年 | 2737篇 |
2017年 | 1960篇 |
2016年 | 2133篇 |
2015年 | 2392篇 |
2014年 | 3668篇 |
2013年 | 5053篇 |
2012年 | 8051篇 |
2011年 | 8460篇 |
2010年 | 4857篇 |
2009年 | 4377篇 |
2008年 | 7589篇 |
2007年 | 7942篇 |
2006年 | 7649篇 |
2005年 | 7295篇 |
2004年 | 7141篇 |
2003年 | 6482篇 |
2002年 | 6140篇 |
2001年 | 1201篇 |
2000年 | 998篇 |
1999年 | 1254篇 |
1998年 | 1351篇 |
1997年 | 1053篇 |
1996年 | 846篇 |
1995年 | 782篇 |
1994年 | 687篇 |
1993年 | 698篇 |
1992年 | 720篇 |
1991年 | 684篇 |
1990年 | 595篇 |
1989年 | 612篇 |
1988年 | 511篇 |
1987年 | 529篇 |
1986年 | 461篇 |
1985年 | 536篇 |
1984年 | 468篇 |
1983年 | 382篇 |
1982年 | 443篇 |
1981年 | 401篇 |
1980年 | 310篇 |
1979年 | 258篇 |
1978年 | 253篇 |
1977年 | 219篇 |
1976年 | 168篇 |
1975年 | 160篇 |
1973年 | 181篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Mark A Rosenthal 《Journal of clinical neuroscience》2004,11(1):66-67
This case report describes the rare phenomenon of encephalopathy associated with massive carcinoid tumor. Extensive investigation failed to reveal an obvious cause but a presumptive diagnosis of tryptophan deficiency was made and she was commenced on tryptophan dietary supplements. A rapid and complete response resulted. This case report discusses this unusual case and reviews the literature regarding carcinoid associated encephalopathy. 相似文献
52.
Sutada Lotinun Glenda L Evans James T Bronk Mark E Bolander Thomas J Wronski Erik L Ritman Russell T Turner 《Journal of bone and mineral research》2004,19(7):1165-1171
We examined the time course effects of continuous PTH on cortical bone and mechanical properties. PTH increased cortical bone turnover and induced intracortical porosity with no deleterious effect on bone strength. Withdrawal of PTH increased maximum torque to failure and stiffness with no change in energy absorbed. INTRODUCTION: The skeletal response of cortical bone to parathyroid hormone (PTH) is complex and species dependent. Intermittent administration of PTH to rats increases periosteal and endocortical bone formation but has no known effects on intracortical bone turnover. The effects of continuous PTH on cortical bone are not clearly established. MATERIALS AND METHODS: Eighty-four 6-month-old female Sprague-Dawley rats were divided into three control, six PTH, and two PTH withdrawal (WD) groups. They were subcutaneously implanted with osmotic pumps loaded with vehicle or 40 microg/kg BW/day human PTH(1-34) for 1, 3, 5, 7, 14, and 28 days. After 7 days, PTH was withdrawn from two groups of animals for 7 (7d-PTH/7d-WD) and 21 days (7d-PTH/21d-WD). Histomorphometry was performed on periosteal and endocortical surfaces of the tibial diaphysis in all groups. microCT of tibias and mechanical testing by torsion of femora were performed on 28d-PTH and 7d-PTH/21d-WD animals. RESULTS AND CONCLUSIONS: Continuous PTH increased periosteal and endocortical bone formation, endocortical osteoclast perimeter, and cortical porosity in a time-dependent manner, but did not change the mechanical properties of the femur, possibly because of addition of new bone onto periosteal and endocortical surfaces. Additionally, withdrawal of PTH restored normal cortical porosity and increased maximum torque to failure and stiffness. We conclude that continuous administration of PTH increased cortical porosity in rats without having a detrimental effect on bone mechanical properties. 相似文献
53.
54.
55.
56.
57.
58.
59.
Guoping Lian Mark E Malone Jenny E Homan Ian T Norton 《Journal of controlled release》2004,98(1):139-155
This paper presents a mathematical model of in-mouth volatile release from gelled emulsion particles dispersed in a continuous aqueous phase. Data based on APCI MS-Breath analysis is presented to demonstrate the effect of particle size, oil content and oil-water partition coefficients. It is shown that in-mouth release of aroma from the dispersion of gelled emulsion particles follows a two-component kinetic equation with fast and slow components. Both the fast and slow rate constants depend on the particle size, oil content and oil water partition coefficient of the aroma. The relative amount of aroma contributing to the fast and slow components also depends on the size of the particles. In order to understand this unexpected behaviour, an analytical model was developed that considers the interplay between the mass transfer of flavour across the interface of the particles and that across the air-liquid interface. Analytical expressions for the two rate constants and the relative ratio of aroma contributing to the fast component have been derived. From this model, three regimes of in-mouth release of aroma from the dispersion of gelled emulsion particles were identified including, the emulsion regime, the transition regime and the gel particle regime. In the emulsion regime, changes in the size of gelled emulsion particles had negligible impact on the overall release. In the transition regime, the release was controlled by the interaction of flavour transfer from the particles with that across the air-water interface. In the gel particle regime, aroma release at long times was governed by the particles and that at short times was governed by the air-water interface, and the two processes were fully decoupled. A simple relationship was derived for the critical size above which the release of aroma from the dispersion of gelled emulsion particles is affected by the size of the particles. 相似文献
60.
Actin cytoskeletal polymerization is associated with a pro-proliferative, pro-survival state. We hypothesized that the actin polymerization of wound cells is increased in the presence of wound matrix attachment and is decreased after disruption of this attachment. Musculocutaneous flap and wound splinting models were used to investigate the effect of wound matrix attachment on the actin cytoskeleton. Disruption of wound matrix attachment was accomplished by incision of the wound matrix/dermis interface (wound matrix release) and/or desplinting. Polymerized actin was assayed with phalloidin labeling of wound specimens 24 hours after disruption of attachment and a method to quantify the content and organization of polymerized actin in granulation tissue was used. Disruption of wound matrix attachment decreased the content of polymerized actin, the actin staining intensity, and the actin fiber organization in the granulation tissue of both the flap and splint models. Disruption of wound matrix attachment decreased actin polymerization and fiber organization in the granulation tissue. Our data support the concept that the state of wound matrix attachment regulates the actin cytoskeleton of wound cells. 相似文献