全文获取类型
收费全文 | 3858篇 |
免费 | 346篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 46篇 |
儿科学 | 140篇 |
妇产科学 | 149篇 |
基础医学 | 619篇 |
口腔科学 | 47篇 |
临床医学 | 571篇 |
内科学 | 610篇 |
皮肤病学 | 52篇 |
神经病学 | 364篇 |
特种医学 | 164篇 |
外科学 | 361篇 |
综合类 | 39篇 |
一般理论 | 5篇 |
预防医学 | 428篇 |
眼科学 | 98篇 |
药学 | 343篇 |
中国医学 | 3篇 |
肿瘤学 | 167篇 |
出版年
2023年 | 26篇 |
2022年 | 23篇 |
2021年 | 80篇 |
2020年 | 51篇 |
2019年 | 90篇 |
2018年 | 84篇 |
2017年 | 83篇 |
2016年 | 82篇 |
2015年 | 72篇 |
2014年 | 120篇 |
2013年 | 177篇 |
2012年 | 249篇 |
2011年 | 243篇 |
2010年 | 130篇 |
2009年 | 113篇 |
2008年 | 185篇 |
2007年 | 211篇 |
2006年 | 221篇 |
2005年 | 205篇 |
2004年 | 178篇 |
2003年 | 174篇 |
2002年 | 150篇 |
2001年 | 77篇 |
2000年 | 82篇 |
1999年 | 66篇 |
1998年 | 45篇 |
1997年 | 41篇 |
1996年 | 29篇 |
1995年 | 35篇 |
1994年 | 27篇 |
1993年 | 36篇 |
1992年 | 64篇 |
1991年 | 66篇 |
1990年 | 55篇 |
1989年 | 49篇 |
1988年 | 56篇 |
1987年 | 62篇 |
1986年 | 41篇 |
1985年 | 42篇 |
1984年 | 24篇 |
1983年 | 22篇 |
1982年 | 26篇 |
1980年 | 18篇 |
1979年 | 36篇 |
1976年 | 19篇 |
1975年 | 19篇 |
1974年 | 23篇 |
1973年 | 23篇 |
1972年 | 19篇 |
1970年 | 21篇 |
排序方式: 共有4206条查询结果,搜索用时 15 毫秒
1.
Few studies have examined the effects of parental incarceration (PI) on outcomes above and beyond other risk and adverse childhood experiences (ACEs). The objectives of this study were to (1) the associations between PI and mental health problems (attention, externalizing, internalizing, and total behavioral problems) and (2) the mediating role of current socioeconomic status and cumulative ACEs. An observational and cross-sectional design was employed. Analyses included hierarchical multivariable linear regression modeling. The analytic sample included 613 adolescents (11–17?years). On average, youth exposed to PI experienced three times as many ACEs compared with youth unexposed. Youth exposed to PI were more likely to have behavioral problems than their unexposed peers. The main effect for all models was attenuated by current economic hardship as well as exposure to increasing numbers of ACEs. Exposure to PI can be viewed as a marker of accumulative risk for intervention since youth impacted by PI are more likely to experience behavioral difficulties and associated adverse childhood experiences. Due to the associated adversity that impact youth exposed to PI, mental health providers need to be able to identify and screen for symptoms associated with trauma. 相似文献
2.
Anna Grace Tribble Phillip Summers Haiying Chen Sara A. Quandt 《Archives of environmental & occupational health》2016,71(6):309-316
The jobs of Latino manual laborers place their mental and physical health at risk. This study evaluates the associations among musculoskeletal pain, mental health, and work organization in Latino manual laborers. Farmworkers and nonfarmworkers (n = 189) in North Carolina were interviewed for self-reported musculoskeletal pain, depressive symptoms, stress, work safety climate, and precarious job status. More nonfarmworkers than farmworkers had neck and shoulder pain, but they did not differ in other areas of musculoskeletal pain. Depressive symptoms had a significant association with neck and shoulder pain (p < .05). Precariousness had a significant association with back pain (p < .05). Farmworker participants had H-2A visas and were afforded some protection compared to nonfarmworker manual workers. Research is needed to improve policy that relieves pain and improves mental health for all Latino manual workers. 相似文献
3.
4.
5.
Complications associated with central venous catheters inserted in critically ill neonates 总被引:2,自引:0,他引:2
V Hruszkewycz P C Holtrop D G Batton R S Morden P Gibson J D Band 《Infection control and hospital epidemiology》1991,12(9):544-548
OBJECTIVE: To assess the incidence and spectrum of complications associated with central venous catheter (CVC) placement in the critically ill infant. DESIGN: A prospective study of all babies hospitalized in a neonatal intensive care unit (NICU) from January 1989 to December 1989. Potential risk factors associated with infection were evaluated by a case-control comparison. SETTING: Conducted at a university-affiliated, tertiary care community hospital. PATIENTS: Neonates requiring intensive care and a central venous catheter. Controls consisted of noninfected babies. RESULTS: Of 263 critically ill neonates, only 13 (4.9%) required a CVC insertion. Seventeen CVCs were placed in these 13 neonates for a total duration of 600 days (median, 32 days/cannula). Fifteen (88%) of these cannulas had one or more complications during its catheter life including dislodgement or leakage (53%), occlusion or thrombosis (47%), infections (29%), or minor bleeding (12%). Five babies (29%) developed 6 episodes of bloodstream infection including 3 sporadic cases due to Staphylococcus epidermidis and a cluster of fungemia due to Malassezia furfur associated with lipid emulsion therapy. Infants with a CVC-associated infection were a younger gestational age (24 weeks versus 32 weeks, p = .04) and weighed less at birth (580 g versus 1285 g, p = .02). The overall rate of bloodstream infection was one episode per 100 days of catheter use. CONCLUSIONS: CVCs may be lifesaving to a critically ill neonate, but complications occur frequently. Use must be restricted to infants in whom alternate delivery routes of intravenous therapy or support are otherwise unavailable. 相似文献
6.
7.
The characteristics of [3H]-prazosin binding in renal cortical membranes of the rat have been assessed under a variety of buffer conditions. At 37 degrees, in Krebs' phosphate and Tris buffer, [3H]-prazosin bound to two sites, a small population of high affinity sites with properties of alpha1-adrenoceptors and a much larger population of low affinity sites with different characteristics. High affinity [3H]-prazosin binding was insensitive to Na+, K+, Ca2+ and Mg2+ ions, but low affinity [3H]-prazosin binding was markedly increased in Krebs' phosphate or sodium phosphate buffer and further enhanced in membranes pretreated with EGTA. Binding was decreased in the presence of Ca2+, the decrease in binding mainly being due to a decrease in the number of low affinity sites labelled by the ligand. Low affinity [3H]-prazosin binding was increased at 37 degrees and relatively insensitive to alpha-adrenoceptor antagonists which were weak competitors while catecholamines failed to compete for low affinity binding. Scatchard plots of [3H]-prazosin binding performed using (-)-noradrenaline (1 mM) to define non-specific binding defined binding only to alpha 1-adrenoceptors. This provides a means of differentiating high and low affinity [3H]-prazosin binding. 相似文献
8.
BACKGROUND: Studies have shown that alcoholics have smaller brain volumes than non-alcoholic cohorts, but an effect of family history (FH) of heavy drinking on brain volume has not been demonstrated. We examined the relationship between an FH of heavy drinking and both brain shrinkage as measured by the ratio of brain volumes to intracranial volume (ICV) as well as maximal brain growth as measured by ICV in early-onset and late-onset alcoholics. METHODS: With T1-weighted resonance imaging, we measured ICV, brain volume, and white and gray matter volume in adult treatment-seeking late-onset and early-onset alcoholics with either a positive or a negative FH of heavy alcohol use, and in healthy control subjects. We also calculated brain shrinkage using a ratio of soft tissue volumes to ICV. RESULTS: The FH positive alcoholic patients had significantly smaller ICVs than FH negative patients, suggesting smaller premorbid brain growth. Brain shrinkage did not correlate with FH. Late-onset alcoholics showed a greater difference in ICV between FH positive and FH negative patients than early-onset alcoholics. Late-onset FH positive patients also had significantly lower IQ scores than late-onset FH negative patients, and IQ scores were correlated with ICV. CONCLUSIONS: These data provide evidence that parental alcohol use might increase risk for alcoholism in offspring in part by a genetic and/or environmental effect that might be related to reduced brain growth. 相似文献
9.
10.