全文获取类型
收费全文 | 25339篇 |
免费 | 1814篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 1035篇 |
妇产科学 | 859篇 |
基础医学 | 2922篇 |
口腔科学 | 312篇 |
临床医学 | 4137篇 |
内科学 | 4757篇 |
皮肤病学 | 444篇 |
神经病学 | 2365篇 |
特种医学 | 384篇 |
外科学 | 2040篇 |
综合类 | 347篇 |
一般理论 | 28篇 |
预防医学 | 3742篇 |
眼科学 | 365篇 |
药学 | 1570篇 |
中国医学 | 34篇 |
肿瘤学 | 1743篇 |
出版年
2023年 | 181篇 |
2022年 | 234篇 |
2021年 | 403篇 |
2020年 | 346篇 |
2019年 | 554篇 |
2018年 | 634篇 |
2017年 | 513篇 |
2016年 | 552篇 |
2015年 | 614篇 |
2014年 | 838篇 |
2013年 | 1333篇 |
2012年 | 1964篇 |
2011年 | 1929篇 |
2010年 | 1087篇 |
2009年 | 1024篇 |
2008年 | 1655篇 |
2007年 | 1819篇 |
2006年 | 1698篇 |
2005年 | 1751篇 |
2004年 | 1662篇 |
2003年 | 1502篇 |
2002年 | 1450篇 |
2001年 | 226篇 |
2000年 | 176篇 |
1999年 | 201篇 |
1998年 | 294篇 |
1997年 | 216篇 |
1996年 | 192篇 |
1995年 | 200篇 |
1994年 | 173篇 |
1993年 | 149篇 |
1992年 | 111篇 |
1991年 | 96篇 |
1990年 | 110篇 |
1989年 | 97篇 |
1988年 | 74篇 |
1987年 | 72篇 |
1986年 | 73篇 |
1985年 | 89篇 |
1984年 | 99篇 |
1983年 | 71篇 |
1982年 | 92篇 |
1981年 | 77篇 |
1980年 | 71篇 |
1979年 | 50篇 |
1978年 | 55篇 |
1977年 | 41篇 |
1975年 | 35篇 |
1973年 | 24篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Insect pest species can have devastating effects on crops. Control of these insect pests is usually achieved by using chemical insecticides. However, there has been much cause for concern with their overuse. Consequently, research has been carried out into alternative forms of control, in particular biological control methods. Recent laboratory studies have indicated that these natural forms of control can induce resistant strains of insect pest. In this paper we present a discrete-time host-pathogen model to describe the interaction between a host (insect species) that can develop a resistant strain and a pathogen (biological control) that can be externally applied to the system. For this model we use a single-state variable for the host population. We show that the proportion of resistance in the population impacts on the viability of the host population. Moreover, when the host population does persist, we explore the interaction between host susceptibility and host population levels. The different scenarios which arise are explained ecologically in terms of trade-offs in intrinsic growth rates, disease susceptibility and intraspecific host competition for the resistant subclass. 相似文献
12.
13.
14.
15.
16.
Michael J. Bernas Robert L. Askew Jane M. Armer Janice N. Cormier 《Current breast cancer reports》2010,2(1):53-58
Lymphedema is an under-recognized, progressive, life-long condition estimated to impact 2-3 million people in the United States.
The incidence of breast cancer related lymphedema varies greatly in the literature largely due to different measurement techniques,
competing thresholds for defining lymphedema, and variation in length of follow-up. Multiple imaging techniques have become
useful for diagnosis. Lymphoscintigraphy is one of the most commonly used, as it can identify pathways of lymphatic drainage,
quantify extent of dermal backflow, and help determine functional and morphologic changes in the lymphatic system. Early detection
and intervention hold the greatest promise of reducing the incidence of lymphedema. Health care providers involved with cancer
patients need to become more educated about lymphedema, aware of current risk-reduction practices, and familiar with methods
of diagnosis and assessment, so that patients with early swelling can be referred to lymphedema treatment specialists at a
time when treatment is more effective. 相似文献
17.
18.
Mark Chaffin Jane F Silovsky Christy Vaughn 《Journal of clinical child and adolescent psychology》2005,34(2):210-222
This study examined the temporal concordance between the onset of childhood anxiety disorders and the points of onset and ending of child sexual abuse (CSA). Sexually abused children (N = 158) were assessed with structured diagnostic interviews. Onset ages for lifetime prevalence anxiety disorders were combined and sequenced with the onset and ending of sexual abuse. Hazard rates were calculated. Departures from the overall linear hazard trajectory for onsets were modeled using piecewise growth curve analyses. Increases from the overall trajectory were found around the point of sexual abuse onset for most childhood anxiety disorders. Decreases were found around the ending of sexual abuse. The risk for developing new anxiety disorders after the onset of sexual abuse showed a positive dose-effect relation with abuse severity. The findings add support to the idea that CSA can have a direct link to childhood anxiety disorders, apart from confounded vulnerability factors, postabuse events, or stable family background factors. The findings are contrasted with those from cross-sectional partial correlation studies that have suggested that there is little direct connection between sexual abuse and mental health outcomes. 相似文献
19.
Roberto Civitelli M.D. Eturo Ogata Louis V. Avioli Gary Stein Samuel Edelstein John A. Eisman Yasuho Nishii Hajime Orimo Jane Lian Takuo Fujita Yasufumi Hayashi Shigeaki Kato Tadashi Kobayashi Hirotoshi Morii Rikushi Morita Toshitaka Nakamura Yoshiki Seino Masataka Shiraki Tatsuo Suda Naoyuki Takahashi Hideaki Takahashi Tastuhiko Tanisawa Akifumi Tokita 《Calcified tissue international》1995,57(6):409-414
20.