全文获取类型
收费全文 | 1230篇 |
免费 | 110篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 89篇 |
妇产科学 | 65篇 |
基础医学 | 118篇 |
口腔科学 | 52篇 |
临床医学 | 181篇 |
内科学 | 240篇 |
皮肤病学 | 32篇 |
神经病学 | 63篇 |
特种医学 | 157篇 |
外科学 | 87篇 |
综合类 | 27篇 |
预防医学 | 76篇 |
眼科学 | 12篇 |
药学 | 85篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 86篇 |
出版年
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 25篇 |
2017年 | 24篇 |
2016年 | 26篇 |
2015年 | 35篇 |
2014年 | 39篇 |
2013年 | 44篇 |
2012年 | 20篇 |
2011年 | 31篇 |
2010年 | 48篇 |
2009年 | 72篇 |
2008年 | 36篇 |
2007年 | 54篇 |
2006年 | 28篇 |
2005年 | 37篇 |
2004年 | 25篇 |
2003年 | 25篇 |
2002年 | 31篇 |
2001年 | 34篇 |
2000年 | 29篇 |
1999年 | 38篇 |
1998年 | 80篇 |
1997年 | 88篇 |
1996年 | 61篇 |
1995年 | 53篇 |
1994年 | 38篇 |
1993年 | 43篇 |
1992年 | 16篇 |
1991年 | 12篇 |
1990年 | 17篇 |
1989年 | 28篇 |
1988年 | 27篇 |
1987年 | 31篇 |
1986年 | 21篇 |
1985年 | 21篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 10篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 14篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1973年 | 5篇 |
1972年 | 3篇 |
1920年 | 2篇 |
排序方式: 共有1388条查询结果,搜索用时 15 毫秒
81.
Satoshi Hisano Winnie Chan Kay Latta Richard J Krieg Jr. James CM Chan 《Clinical and experimental nephrology》1997,1(3):179-186
Growth retardation is a major complication in children with uremia. Protein restriction, calorie deficit, metabolic acidosis,
renal osteodystrophy, and endocrinologic disturbances contribute to the growth failure. The effect of these factors on growth
retardation can be attenuated in part by therapy with vitamin D metabolites, adequate nutrition, alkalization, and dialysis.
Linear growth in children with uremia is markedly retarded despite normal or increased levels of circulating serum growth
hormone. An increased growth hormone level in children with uremia is due to normal growth hormone secretion from the pituitary
gland and impaired growth hormone clearance in the kidney. However, the elevated growth hormone level does not lead to a commensurate
rise in serum insulin-like growth factor I (IGF-I); the serum IGF-I level is decreased or normal in relation to the degree
of renal failure. This discrepancy suggests growth hormone resistance in the liver in uremia. Recent molecular techniques
open a new era in studying the gene expression for growth hormone or IGF-I. There is no doubt today that growth hormone treatment
has the beneficial effect of growth promotion in children with uremia, which also suggests endogenous growth hormone resistance
in target organs or target cells in uremia. 相似文献
82.
Molly McCarthy Ushma Upadhyay M. Antonia Biggs Renaisa Anthony Jennifer Holl Sarah CM Roberts 《Contraception》2018,97(4):303-308
Objective
Earlier pregnancy discovery is important in the context of prenatal and abortion care. We evaluated characteristics associated with later pregnancy discovery among women seeking abortion care.Study design
Data come from a survey of women seeking abortion care at four family planning facilities in Utah. The participants completed a survey during the state-mandated abortion information visit they are required to complete prior to having an abortion. The outcome in this study was pregnancy discovery before versus after 6 weeks since respondents' last menstrual period (LMP). We used logistic regression to estimate the relationship between sociodemographic and health-related independent variables of interest and pregnancy discovery before versus after 6 weeks.Results
Among the 458 women in the sample, 28% discovered their pregnancy later than 6 weeks since LMP. Most (n=366, 80%) knew the exact date of their LMP and a significant minority estimated it (n=92, 20%). Those who estimated the date of their LMP had higher odds of later pregnancy discovery than those who knew the exact date (adjusted odds ratio (aOR) = 1.81[1.07–3.07]). Those who used illicit drugs weekly, daily, or almost daily had higher odds of later pregnancy discovery (aOR=6.33[2.44, 16.40]).Conclusion
Women who did not track their menstrual periods and those who frequently used drugs had higher odds of discovering their pregnancies later.Implications
Women who estimated the date of their LMP and who frequently used drugs may benefit from strategies to help them recognize their pregnancies earlier and link them to care when they discover their pregnancies later. 相似文献83.
Laura D. Byham‐Gray PhD RDN J. Scott Parrott PhD Emily N. Peters MPH Susan Gould Fogerite PhD Rosa K. Hand MS RDN Sean Ahrens MLS CM Andrea Fleisch Marcus PhD MPH Justin J. Fiutem MS RCEP 《JPEN. Journal of parenteral and enteral nutrition》2018,42(3):587-596
Background: Hypermetabolism is theorized in patients diagnosed with chronic kidney disease who are receiving maintenance hemodialysis (MHD). We aimed to distinguish key disease‐specific determinants of resting energy expenditure to create a predictive energy equation that more precisely establishes energy needs with the intent of preventing protein‐energy wasting. Materials and Methods: For this 3‐year multisite cross‐sectional study (N = 116), eligible participants were diagnosed with chronic kidney disease and were receiving MHD for at least 3 months. Predictors for the model included weight, sex, age, C‐reactive protein (CRP), glycosylated hemoglobin, and serum creatinine. The outcome variable was measured resting energy expenditure (mREE). Regression modeling was used to generate predictive formulas and Bland‐Altman analyses to evaluate accuracy. Results: The majority were male (60.3%), black (81.0%), and non‐Hispanic (76.7%), and 23% were ≥65 years old. After screening for multicollinearity, the best predictive model of mREE (R2 = 0.67) included weight, age, sex, and CRP. Two alternative models with acceptable predictability (R2 = 0.66) were derived with glycosylated hemoglobin or serum creatinine. Based on Bland‐Altman analyses, the maintenance hemodialysis equation that included CRP had the best precision, with the highest proportion of participants’ predicted energy expenditure classified as accurate (61.2%) and with the lowest number of individuals with underestimation or overestimation. Conclusions: This study confirms disease‐specific factors as key determinants of mREE in patients on MHD and provides a preliminary predictive energy equation. Further prospective research is necessary to test the reliability and validity of this equation across diverse populations of patients who are receiving MHD. 相似文献
84.
85.
86.
Glucagon‐Like Peptide‐2 Alters Bile Acid Metabolism in Parenteral Nutrition–Associated Liver Disease 下载免费PDF全文
87.
Background
We examined the association of alcohol use disorders (AUD) with adherence to and health-related quality of life (HRQOL) outcomes of antiretroviral treatment (ART) for HIV/AIDS patients.Methods
A cross-sectional multi-site survey was conducted in 468 drug users and 648 non-drug users (age: 35.4 ± 7.0 years; 63.8% male) in 3 epicentres of Vietnam. AUD, ART adherence, and HRQOL were measured using the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C), the self-reported Visual Analogue Scale (VAS), and the World Health Organization Quality of Life instrument (WHOQOL-HIV BREF).Results
35.0% of drug users were hazardous drinkers, compared to 25.9% of non-drug users. 22.3% of drug users engaged in binge drinking, and 25.9% reported suboptimal ART adherence. Adjusting for propensity scores of AUD, patients who had either at-risk or binge drinking behaviour were about twice as likely to be treatment non-adherent as those who did not have AUD. Hazardous drinkers reported small to medium decrements in the Performance, Physical, Social, Spirituality, and Environment quality of life domains. Binge drinkers had a slightly higher score in Social dimension.Conclusion
AUD is prevalent and negatively affecting adherence to and HRQOL outcomes of ART services in injection-driven HIV epidemics. Screening and intervention are recommended for AUD, especially during the stable periods of ART. Other social and psychological interventions might also enhance patients’ responses to and outcomes of ART in Vietnam. 相似文献88.
89.
Marleen?J?NahuisEmail author Nienke?S?Weiss Fulco?van der Veen Ben?Willem?J?Mol Peter?G?Hompes Jur?Oosterhuis Nils?B?Lambalk Jesper?MJ?Smeenk Carolien?AM?Koks Ron?JT?van Golde Joop?SE?Laven Ben?J?Cohlen Kathrin?Fleischer Angelique?J?Goverde Marie?H?Gerards Nicole?F?Klijn Lizka?CM?Nekrui Ilse?AJ?van Rooij Diederik?A?Hoozemans Madelon?van Wely 《BMC women's health》2013,13(1):42
Background
Clomiphene citrate (CC) is first line treatment in women with World Health Organization (WHO) type II anovulation and polycystic ovary syndrome (PCOS). Whereas 60% to 85% of these women will ovulate on CC, only about one half will have conceived after six cycles. If women do not conceive, treatment can be continued with gonadotropins or intra-uterine insemination (IUI). At present, it is unclear for how many cycles ovulation induction with CC should be repeated, and when to switch to ovulation induction with gonadotropins and/or IUI.Methods/Design
We started a multicenter randomised controlled trial in the Netherlands comparing six cycles of CC plus intercourse or six cycles of gonadotrophins plus intercourse or six cycles of CC plus IUI or six cycles of gonadotrophins plus IUI.Women with WHO type II anovulation who ovulate but did not conceive after six ovulatory cycles of CC with a maximum of 150 mg daily for five days will be included.Our primary outcome is birth of a healthy child resulting from a pregnancy that was established in the first eight months after randomisation. Secondary outcomes are clinical pregnancy, miscarriage, multiple pregnancy and treatment costs. The analysis will be performed according to the intention to treat principle. Two comparisons will be made, one in which CC is compared to gonadotrophins and one in which the addition of IUI is compared to ovulation induction only. Assuming a live birth rate of 40% after CC, 55% after addition of IUI and 55% after ovulation induction with gonadotrophins, with an alpha of 5% and a power of 80%, we need to recruit 200 women per arm (800 women in total).An independent Data and Safety Monitoring Committee has criticized the data of the first 150 women and concluded that a sample size re-estimation should be performed after including 320 patients (i.e. 80 per arm).Discussion
The trial will provide evidence on the most effective, safest and most cost effective treatment in women with WHO type II anovulation who do not conceive after six ovulatory cycles with CC with a maximum of 150 mg daily for five days. This evidence could imply the need for changing our guidelines, which may cause a shift in large practice variation to evidence based primary treatment for these women.Trial registration number
Netherlands Trial register NTR144990.
Splettstoesser F Bonnet U Wiemann M Bingmann D Büsselberg D 《British journal of pharmacology》2005,144(1):52-58
Harmala alkaloids are endogenous substances, which are involved in neurodegenerative disorders such as M. Parkinson, but some of them also have neuroprotective effects in the nervous system.While several sites of action at the cellular level (e.g. benzodiazepine receptors, 5-HT and GABA(A) receptors) have been identified, there is no report on how harmala alkaloids interact with voltage-gated membrane channels.The aim of this study was to investigate the effects of harmaline and harmane on voltage-activated calcium- (I(Ca(V))), sodium- (I(Na(V))) and potassium (I(K(V)))-channel currents, using the whole-cell patch-clamp method with cultured dorsal root ganglion neurones of 3-week-old rats. Currents were elicited by voltage steps from the holding potential to different command potentials.Harmaline and harmane reduced I(Ca(V)), I(Na(V)) and I(K(V)) concentration-dependent (10-500 microM) over the voltage range tested. I(Ca(V)) was reduced with an IC(50) of 100.6 microM for harmaline and by a significantly lower concentration of 75.8 microM (P<0.001, t-test) for harmane. The Hill coefficient was close to 1. Threshold concentration was around 10 microM for both substances.The steady state of inhibition of I(Ca(V)) by harmaline or harmane was reached within several minutes. The action was not use-dependent and at least partly reversible. It was mainly due to a reduction in the sustained calcium channel current (I(Ca(L+N))), while the transient voltage-gated calcium channel current (I(Ca(T))) was only partially affected. We conclude that harmaline and harmane are modulators of I(Ca(V)) in vitro. This might be related to their neuroprotective effects. 相似文献