全文获取类型
收费全文 | 100341篇 |
免费 | 29395篇 |
国内免费 | 1098篇 |
专业分类
耳鼻咽喉 | 2450篇 |
儿科学 | 2683篇 |
妇产科学 | 2373篇 |
基础医学 | 2763篇 |
口腔科学 | 5115篇 |
临床医学 | 25964篇 |
内科学 | 25447篇 |
皮肤病学 | 3340篇 |
神经病学 | 12507篇 |
特种医学 | 3625篇 |
外科学 | 18370篇 |
综合类 | 122篇 |
现状与发展 | 40篇 |
一般理论 | 3篇 |
预防医学 | 13350篇 |
眼科学 | 2139篇 |
药学 | 1214篇 |
中国医学 | 15篇 |
肿瘤学 | 9314篇 |
出版年
2024年 | 742篇 |
2023年 | 5050篇 |
2022年 | 1148篇 |
2021年 | 2804篇 |
2020年 | 5344篇 |
2019年 | 2061篇 |
2018年 | 6909篇 |
2017年 | 7347篇 |
2016年 | 7959篇 |
2015年 | 8034篇 |
2014年 | 10429篇 |
2013年 | 12144篇 |
2012年 | 3795篇 |
2011年 | 3511篇 |
2010年 | 6829篇 |
2009年 | 9110篇 |
2008年 | 3514篇 |
2007年 | 2470篇 |
2006年 | 3652篇 |
2005年 | 2190篇 |
2004年 | 1585篇 |
2003年 | 1220篇 |
2002年 | 1133篇 |
2001年 | 2016篇 |
2000年 | 1361篇 |
1999年 | 1832篇 |
1998年 | 2100篇 |
1997年 | 1942篇 |
1996年 | 2000篇 |
1995年 | 1720篇 |
1994年 | 1110篇 |
1993年 | 929篇 |
1992年 | 855篇 |
1991年 | 730篇 |
1990年 | 595篇 |
1989年 | 596篇 |
1988年 | 571篇 |
1987年 | 449篇 |
1986年 | 410篇 |
1985年 | 349篇 |
1984年 | 321篇 |
1983年 | 338篇 |
1982年 | 251篇 |
1981年 | 220篇 |
1980年 | 140篇 |
1979年 | 101篇 |
1978年 | 147篇 |
1977年 | 128篇 |
1976年 | 112篇 |
1974年 | 87篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Using the concepts of stigma, NIMBY and place, this paper examines the difficulties of finding a place for needle exchange programs (NEPs). Data were drawn from semi-structured interviews with NEP staff (Ontario, Canada) that focused on operational policies and routines. An iterative, inductive analytic process was used. NEPs, their staff and clients are not always welcome additions to organizations or communities because of concerns about the ‘dangerousness’ of clients and the potential contamination of communities and workplaces by stigmatized individuals and their artefacts (e.g. contaminated injection equipment). Public parks where a lot of drug ‘action’ takes place are good destinations for outreach workers but these places are contentious sites for NEP activities, particularly when residents do not perceive a need for the program and/or want to redefine their neighbourhoods. Issues of ‘place’ are further complicated when service delivery is mobile. Finding a place within organizations is difficult for NEPs because of concerns about the diversion of limited financial and spatial resources to ‘non-core’ activities and ‘undesirable’ clients. Workers respond to these challenges by contesting the social and spatial boundaries of who is an acceptable client or neighbour and refuting the perceived ‘differentness’ of injection drug users. Implementation of an unpopular service involves a delicate balancing act of interests, understanding of the dynamics of particular communities and a willingness to reinvent and redefine programs. The sociospatial stigmatization of injection drug use has had a negative impact on NEPs, and perhaps limits HIV prevention efforts. 相似文献
94.
Sami R Achem MD Alexander Klaus MD Ronald A Hinder MD PhD Kenneth R DeVault MD 《The American journal of medicine》2004,116(10):717-718
95.
96.
97.
98.
99.
C Vassanelli G Menegatti B Silverstein P Zardini R Cubeddu V Russo O Svelto 《Lasers in surgery and medicine》1987,7(1):23-28
Percutaneous transluminal balloon angioplasty (PTA) is being currently used in patients with coronary artery disease. Laser irradiation (LI) has been effective in vaporizing atherosclerotic plaques. The purpose of this work was twofold: to compare PTA and LI techniques in the recanalization of experimental obstructive arterial lesions, and to evaluate the possibility of reducing the failures and local complications and increasing the success rate of PTA by the combined use of LI. Atherosclerotic iliac stenoses were induced in 27 rabbits; lesions were evaluated angiographically before and after intervention and were studied histologically and by electron microscopy. Argon-ion LI delivered through microlens-tip optic fibers reduced the stenotic area from 64.2 +/- 21.8% to 40.3 +/- 10.7% (n = 10, P less than .01) and PTA from 60.7 +/- 15.9% to 30.4 +/- 7.7% (n = 9, P less than .01). However, percentage reduction was higher in PTA-treated stenoses (48.4 +/- 10.1% vs 34.5 +/- 13.5%, P less than .0125). In eight more rabbits, low power LI (4.55 +/- 1.25 J) was delivered after PTA in dilated segments. Post-PTA LI further decreased stenoses (from 31.2 +/- 7.8% to 29.1 +/- 8.1%, P less than .0125); laser-irradiated segments showed diffuse carbonization of the disrupted intimal layer. The normalized transtenotic pressure gradient decreased significantly in all groups: LI reduced the gradient from .40 +/- .25 to .17 +/- .07 (P = .005); PTA from .37 +/- .14 to .11 +/- .04 (P = .001); LI after PTA from .40 +/- .16 to .12 +/- .06 (P = .001). Thus, LI is effective (less than PTA) in relieving experimental atherosclerotic stenoses and seems useful when combined with PTA. 相似文献
100.
Effects of intermittent diethylstilbestrol diphosphate administration on the R3327 rat prostatic carcinoma 总被引:1,自引:0,他引:1
P Russo G Liguori W D Heston R Huryk C R Yang W R Fair W F Whitmore H W Herr 《Cancer research》1987,47(22):5967-5970
Clinical trials have utilized intermittent diethylstilbestrol diphosphate (DES) therapy in advanced symptomatic prostatic carcinoma to diminish the morbidity of standard endocrine therapy. To determine the effect of intermittent DES administration on the Dunning R3327 rat prostatic adenocarcinoma 60 days following tumor implant, 6 groups were randomly assigned: control (N = 8), castrate (N = 10), high dose DES (N = 8, 1.6 micrograms/ml DES continuously in drinking water), low dose DES (N = 10, 0.4 microgram/ml continuously in drinking water), intermittent high dose DES (N = 10, 1.6 micrograms/ml DES in drinking water for 1 week, then off for 3 weeks), and intermittent low dose DES (N = 10, 0.4 microgram/ml DES for 1 week, then off for 3 weeks). Results indicate that low or high dose DES, and intermittent low or intermittent high dose DES during the week of administration were able to reduce serum testosterone to castrate levels (0.1 ng/ml). After withdrawal of intermittent DES, serum testosterone returned toward control levels (1.0 ng/ml). Initial mean tumor burden between control and treatment groups was not significantly different. All DES exposed rats had a tumor volume at death (range, 15.6-18.3 cm3) smaller than control (mean, 25.4 cm3) or castrate (mean, 40.8 cm3) rats. Despite this significant survival advantage from the time of randomization was achieved only in castrate (median survival, 331 days) or high dose DES (median survival, 359 days) groups compared to control (median survival, 225 days). Similarly, significant prolongation in tumor doubling time was achieved only by rats receiving castration or high dose DES. Intermittent DES administration controls tumor volume but does not provide a survival advantage. In this respect, intermittent DES is inferior to castration. 相似文献