全文获取类型
收费全文 | 19634篇 |
免费 | 1536篇 |
国内免费 | 58篇 |
专业分类
耳鼻咽喉 | 192篇 |
儿科学 | 855篇 |
妇产科学 | 591篇 |
基础医学 | 2562篇 |
口腔科学 | 267篇 |
临床医学 | 2257篇 |
内科学 | 3874篇 |
皮肤病学 | 314篇 |
神经病学 | 2116篇 |
特种医学 | 366篇 |
外科学 | 1940篇 |
综合类 | 140篇 |
一般理论 | 11篇 |
预防医学 | 2529篇 |
眼科学 | 318篇 |
药学 | 1261篇 |
1篇 | |
中国医学 | 34篇 |
肿瘤学 | 1600篇 |
出版年
2024年 | 24篇 |
2023年 | 210篇 |
2022年 | 380篇 |
2021年 | 726篇 |
2020年 | 463篇 |
2019年 | 706篇 |
2018年 | 845篇 |
2017年 | 614篇 |
2016年 | 587篇 |
2015年 | 635篇 |
2014年 | 868篇 |
2013年 | 1168篇 |
2012年 | 1650篇 |
2011年 | 1793篇 |
2010年 | 911篇 |
2009年 | 809篇 |
2008年 | 1235篇 |
2007年 | 1285篇 |
2006年 | 1157篇 |
2005年 | 1026篇 |
2004年 | 955篇 |
2003年 | 795篇 |
2002年 | 725篇 |
2001年 | 193篇 |
2000年 | 192篇 |
1999年 | 168篇 |
1998年 | 109篇 |
1997年 | 97篇 |
1996年 | 84篇 |
1995年 | 57篇 |
1994年 | 54篇 |
1993年 | 45篇 |
1992年 | 65篇 |
1991年 | 61篇 |
1990年 | 61篇 |
1989年 | 50篇 |
1988年 | 47篇 |
1987年 | 54篇 |
1986年 | 57篇 |
1985年 | 40篇 |
1984年 | 37篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 16篇 |
1980年 | 14篇 |
1979年 | 13篇 |
1978年 | 11篇 |
1975年 | 11篇 |
1974年 | 12篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Taking advantage of two large, population-based, and longitudinal datasets collected after the 1999 floods in Mexico (n = 561) and the September 11, 2001 terrorist attacks in New York (n = 1267), we examined the notion that resilience may be best understood and measured as one member of a set of trajectories that may follow exposure to trauma or severe stress. We hypothesized that resistance, resilience, recovery, relapsing/remitting, delayed dysfunction, and chronic dysfunction trajectories were all possible in the aftermath of major disasters. Semi-parametric group-based modeling yielded the strongest evidence for resistance (no or mild and stable symptoms), resilience (initially moderate or severe symptoms followed by a sharp decrease), recovery (initially moderate or severe symptoms followed by a gradual decrease), and chronic dysfunction (moderate or severe and stable symptoms), as these trajectories were prevalent in both samples. Neither Mexico nor New York showed a relapsing/remitting trajectory, and only New York showed a delayed dysfunction trajectory. Understanding patterns of psychological distress over time may present opportunities for interventions that aim to increase resilience, and decrease more adverse trajectories, after mass traumatic events. 相似文献
42.
43.
This article describes the process and outcome of a needs assessment conducted to guide the development of interventions to increase repeat mammography use among participants in a federally funded cancer screening program. Health behavior theory and data from a phone survey are used to uncover key barriers to repeat mammography use and to identify fruitful intervention approaches for modifying them. Estimates of (a) compliance with mammography guidelines, (b) readiness to adopt regular mammography use, (c) the most common reasons for not being rescreened, and (d) population attributable risks associated with various predictors of repeat mammography use are presented and, with guidance from the transtheoretical model of behavior change, used to make inferences about the type of intervention strategies most appropriate for promoting repeat mammography use in this population. 相似文献
44.
45.
Rats and guinea pigs were exposed to 0.8 mg ozone (O3)/m3 (approximately 0.4 ppm) for 12 hr during the daytime, 12 hr during the nighttime, or continuously to investigate circadian variation in O3-induced pulmonary toxicity during single and repeated O3 exposures. Biomarkers in bronchoalveolar lavage (BAL) fluid and lung tissues were measured as indicators of biochemical and inflammatory responses. Nighttime O3 exposure of rats resulted in larger increases of protein, albumin, and inflammatory cells in BAL fluid compared to those after daytime O3 exposure and this daytime-nighttime difference was statistically significant (p < 0.05). Single daytime or nighttime O3 exposure of guinea pigs resulted in comparable increases of BAL fluid proteins and inflammatory cells without a daytime-nighttime difference. Nighttime and continuous O3 exposure of rats for 3 days resulted in comparable increases in lung antioxidant enzyme activities, both of which differed statistically from effects from daytime O3 exposures (p < 0.05). Continuous O3 exposure of guinea pigs for 3 days caused, in general, statistically larger increases in lung tissue parameters compared to nighttime O3 exposures (p < 0.05). These results suggest that the extent of O3-induced acute pulmonary biochemical and inflammatory responses is directly related to the level of physical and respiratory activity. For rats, effects from continuous O3 exposure appear to be controlled by the nighttime, physically active period. In guinea pigs, the comparable responses following daytime or nighttime O3 exposure seem in accordance with their random behavioral daily activity pattern. This study supports the view that physical activity-related increases in inhaled dose significantly enhance the pulmonary O3 responses. 相似文献
46.
Kelvin L Chou Maria L Moro-De-Casillas Melissa M Amick Leora L Borek Joseph H Friedman 《Movement disorders》2007,22(3):411-414
We examined the relationship between testosterone levels, violent dreams, and REM sleep behavior disorder (RBD) in 31 men with Parkinson's disease (PD): 12 with clinical RBD and 19 without. All PD patients with clinical RBD experienced violent dreams, but none of the 19 non-RBD patients reported violent dreams. While dream content appears to be more aggressive in PD patients with clinical RBD, the presence of violent dreams or clinical RBD is not associated with testosterone levels in men with PD. 相似文献
47.
48.
Keith J. Slifer Melissa Beck Adrianna Amari Tanya Diver Lisa Hilley Alana Kane Sharon McDonnell 《Children's Health Care》2003,32(2):81-101
This study investigated relationships between child/parent dissatisfaction with child facial appearance and the self-concept/social competence of 8- to 15-year-old children with (N = 34) and without (N = 34) oral clefts. Children in both groups had normative psychosocial adjustment, but also reported moderate dissatisfaction with facial appearance. Cleft group parents were more likely to agree with their child's dissatisfaction. When cleft group parents were more dissatisfied with child facial appearance, their children reported better quality of life. Results suggest that parents of children with clefts reporting greater dissatisfaction may respond in positive ways that enhance quality of life. 相似文献
49.
The American Board of Nursing Specialties (ABNS) conducted a survey to determine the value professional nurses place on nursing certification as well as barriers to certification. This article presents an overview of the survey results in general and specifically the views of nephrology nurse participants. 相似文献
50.
Bradley S Daines Alexander R Kent Melissa S McAleer Craig E Crosson 《Journal of ocular pharmacology and therapeutics》2003,19(2):113-119
PURPOSE: Adenosine receptors modulate several ocular responses; however, our understanding of factors that influence ocular extracellular adenosine levels is limited. The objective of this study was to evaluate how changes in intraocular pressure (IOP) influence endogenous levels of the purines adenosine and inosine, in the aqueous humor of normal and ocular-hypertensive patients. PATIENTS AND METHODS: Informed consent was obtained from 51 individuals undergoing cataract extraction or glaucoma surgical procedures. IOP was measured immediately prior to surgery. At the start of the surgical procedure, an aqueous sample of 75-100 microL was obtained. Purine levels were determined by reverse-phase HPLC. RESULTS: In normotensive individuals, mean aqueous adenosine and inosine levels were 5.2 +/- 1.1 and 19.4 +/- 2.2 ng/100 microL, respectively. No significant correlation between IOP and purine concentration was measured in this group. In ocular hypertensive individuals, the mean aqueous adenosine and inosine concentration was significantly elevated when compared to normotensive individuals. In the ocular hypertensive individual, this elevation in adenosine level was significantly correlated with IOP (r(2) = 0.42). CONCLUSIONS: These results demonstrate that in ocular hypertensive individuals, aqueous adenosine concentration is correlated with IOP. As the activation of adenosine receptors can modulate IOP and retinal blood flow, adenosine release during periods of ocular hypertension may play an important role in the physiological responses to elevated IOP. 相似文献