全文获取类型
收费全文 | 1022篇 |
免费 | 26篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 53篇 |
妇产科学 | 18篇 |
基础医学 | 75篇 |
口腔科学 | 16篇 |
临床医学 | 136篇 |
内科学 | 239篇 |
皮肤病学 | 34篇 |
神经病学 | 43篇 |
特种医学 | 263篇 |
外科学 | 48篇 |
综合类 | 28篇 |
预防医学 | 51篇 |
眼科学 | 22篇 |
药学 | 52篇 |
中国医学 | 3篇 |
肿瘤学 | 40篇 |
出版年
2023年 | 5篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 10篇 |
2015年 | 13篇 |
2014年 | 16篇 |
2013年 | 15篇 |
2012年 | 17篇 |
2011年 | 21篇 |
2010年 | 35篇 |
2009年 | 50篇 |
2008年 | 22篇 |
2007年 | 51篇 |
2006年 | 25篇 |
2005年 | 29篇 |
2004年 | 17篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 25篇 |
2000年 | 25篇 |
1999年 | 11篇 |
1998年 | 82篇 |
1997年 | 70篇 |
1996年 | 59篇 |
1995年 | 51篇 |
1994年 | 43篇 |
1993年 | 44篇 |
1992年 | 21篇 |
1991年 | 16篇 |
1990年 | 22篇 |
1989年 | 34篇 |
1988年 | 34篇 |
1987年 | 26篇 |
1986年 | 22篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 10篇 |
1980年 | 13篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 16篇 |
1976年 | 13篇 |
1975年 | 13篇 |
1958年 | 2篇 |
1900年 | 2篇 |
排序方式: 共有1123条查询结果,搜索用时 15 毫秒
61.
Effect of low-calorie parenteral nutrition on the incidence and severity of hyperglycemia in surgical patients: a randomized, controlled trial 总被引:6,自引:0,他引:6
Ahrens CL Barletta JF Kanji S Tyburski JG Wilson RF Janisse JJ Devlin JW 《Critical care medicine》2005,33(11):2507-2512
OBJECTIVE: To determine the effect of a low-calorie parenteral nutrition (PN) regimen on the incidence and severity of hyperglycemia and insulin requirements. DESIGN: Prospective, randomized, clinical trial. SETTING: Urban, university-affiliated, level-I trauma center. PATIENTS: Consecutive surgical patients requiring PN. INTERVENTIONS: Patients were randomized to receive either a low-calorie PN formulation (20 nonprotein kilocalories per kg per day) or a standard PN formulation (30 nonprotein kilocalories per kg per day). Lipid-derived calories were standardized to 1000 kilocalories three times weekly for all patients; consequently, the number of calories varied only by the amount of carbohydrate administered. Protein requirements were individualized on the basis of estimated metabolic stress. Hyperglycemia was defined as a blood glucose level > or = 200 mg/dL. MEASUREMENTS AND MAIN RESULTS: Forty patients were evaluated (low-calorie PN, n = 20; standard PN, n = 20). Demographics of the two groups were similar. The incidence of hyperglycemic events was significantly lower in the low-calorie group (0% [0-0.5] vs. 33.1% [0-58.4]; p = .001]. Additionally, the severity of hyperglycemia was also lower in the low-calorie group (mean glucose area under the curve = 118 +/- 22 [mg x hr]/dL vs. 172 +/- 44 [mg x hr]/dL; p < .001). This resulted in lower average daily insulin requirements (0 [0-0] units vs. 10.9 [0-25.6] units; p < .001.). The only predictor of hyperglycemia was a dextrose administration rate >4 mg/kg/min. CONCLUSIONS:: Administration of a low-calorie PN formulation resulted in fewer and less-severe hyperglycemic events and lower insulin requirements. PN regimens should not exceed a dextrose administration rate of 4 mg/kg/min to avoid hyperglycemic events. 相似文献
62.
Postembolic colonic infarction 总被引:12,自引:0,他引:12
63.
64.
65.
66.
Delaney-Black V Covington C Nordstrom B Ager J Janisse J Hannigan JH Chiodo L Sokol RJ 《Journal of developmental and behavioral pediatrics : JDBP》2004,25(4):254-263
Animal but few human studies have demonstrated gender-influenced differences in outcome related to prenatal cocaine exposure. Pregnant participants in a prospective pregnancy study were interviewed for drug use. Exposure was considered positive if history or laboratory tests were positive. An ordinal measure of exposure was also constructed. Six years later, the child and primary caretaker were tested to assess drug use in the home since birth and teacher-assessed child behavior. Data were complete for 473 children (204 cocaine exposed). Twenty-four of the exposed children (12%) were considered to have persistent pregnancy exposure based on positive urine screen at delivery. Boys with any prenatal cocaine exposure scored significantly higher (more problem behaviors) than nonexposed boys on the hyperactivity item. In contrast, no similar cocaine effect was observed for girls. When cocaine exposure was expressed as the three-level ordinal variable, boys, but not girls, with persistent exposure had more behavior problems (0.5 to 1.0 SD higher). Even after control for important covariates, boys with persistent exposure had more problems in central processing, motor skills, handling abstract concepts, and passivity to the environment. The magnitude of the relations reported in this research were moderate to large. In summary, both gender and the level of exposure had a significant behavioral effect on school-age behavior. In these analyses, the behavior of boys, but not girls, prenatally exposed to cocaine was significantly and negatively affected, and these findings remained after control for covariates, including prenatal alcohol or other illicit drug exposures and postnatal drug use in the home. 相似文献
67.
Bailey BN Delaney-Black V Covington CY Ager J Janisse J Hannigan JH Sokol RJ 《American journal of obstetrics and gynecology》2004,191(3):1037-1043
OBJECTIVE: The goal of this study was to examine differential effects of amount and pattern of prenatal alcohol exposure on child outcome. STUDY DESIGN: Alcohol use was assessed at each prenatal visit, and IQ and behavior were measured at age 7 years. RESULTS: After control for confounders, the amount of exposure was unrelated to IQ score and behavior for >500 black 7-year-old children. However, children who were exposed to binge drinking were 1.7 times more likely to have IQ scores in the mentally retarded range and 2.5 times more likely to have clinically significant levels of delinquent behavior. CONCLUSION: During prenatal care, clinicians should attend not only to amount but also to the pattern of alcohol intake, because of the elevated risk for cognitive deficits and long-term behavioral abnormality. 相似文献
68.
Foot orthoses have been effective in the treatment of a variety of sport-related foot conditions. Although their use is well-established in clinical practice, many of the orthoses have not been evaluated in experimental conditions. Of the clinical studies that have examined the biomechanical changes associated with their use, many do not have predictable results. The failure of some studies to find trends for a particular variable does not preclude this variable being affected by the orthoses in an individual patient; rather, it may speak to the highly subject-specific responses with orthotic use. It is important to recognize that foot orthoses cannot be considered independent of a rehabilitation protocol that includes stretching and strengthening-specific therapies, as well as a consideration of training surfaces and training regimes. Additionally, foot orthoses must be considered in concert with the foot-wear recommendation. 相似文献
69.
Bell EC Baker GB Poag C Bellavance F Khudabux J Le Mellédo JM 《Psychopharmacology》2004,172(3):248-254
Rationale Animal studies of short-term progesterone administration and withdrawal model the natural increase and abrupt decrease in progesterone levels which occur in the late luteal phase (LP) of the human menstrual cycle (MC). Previously, studies in animals have shown that abrupt cessation of chronic or short-term progesterone administration results in pharmacological changes at the GABAA receptor, resulting in altered sensitivity to GABAA receptor neuromodulators such as benzodiazepines and flumazenil, a GABAA receptor antagonist.Objectives This studys goal was to compare the response to flumazenil in the follicular phase (FP) and late LP in female healthy controls (HCs). We postulated that HC females would exhibit a greater psychological and somatic response to flumazenil in the late LP, a period of progesterone withdrawal, compared to the FP.Methods Twelve healthy females, without history of psychiatric disorder, were randomized to receive two injections of a 2 mg bolus injection of flumazenil (one in the late LP and one in the FP) and two injections of placebo (one in the late LP and one in the FP). Following injection, subjects were asked to rate the occurrence and intensity of panic symptoms on the panic symptom scale (PSS).Results A main treatment effect was detected for the PSS score response after flumazenil injection (P=0.008). However, there was no significant treatment-by-phase interaction observed (P=0.449).Conclusions These findings indicate that MC phase did not affect the response to flumazenil in HC females. This result is contrary to our hypothesis of altered sensitivity to flumazenil in the late LP. 相似文献
70.
The literature indicates that mood is an important predictor of physical and psychological well-being. Mood influences a person's health perceptions, treatment compliance, and recovery. Given the importance of mood as an outcome, it is important to identify predictors of mood. The current study examined physical activity, social support, and family structure as determinants of mood among women who had recently begun a walking program. Two hundred and fifty-nine European-American and African-American women between the ages of 30 and 60 participated in the study. A significant positive relation was found between physical activity, social support, and mood, while a negative relation was found between number of children and mood. Hierarchical regression revealed that physical activity, social support of friends, mari- tal status, and number of children were significant predictors of women's mood. Race moderated the relation between number of children and mood. This study suggests that physical activity, social support, and family may be important factors in the psychological well-being of women. 相似文献