全文获取类型
收费全文 | 66213篇 |
免费 | 6424篇 |
国内免费 | 120篇 |
专业分类
耳鼻咽喉 | 922篇 |
儿科学 | 1917篇 |
妇产科学 | 1597篇 |
基础医学 | 9571篇 |
口腔科学 | 1581篇 |
临床医学 | 8415篇 |
内科学 | 12317篇 |
皮肤病学 | 906篇 |
神经病学 | 5570篇 |
特种医学 | 2151篇 |
外国民族医学 | 1篇 |
外科学 | 9527篇 |
综合类 | 1210篇 |
一般理论 | 48篇 |
预防医学 | 6524篇 |
眼科学 | 1139篇 |
药学 | 5284篇 |
中国医学 | 79篇 |
肿瘤学 | 3998篇 |
出版年
2022年 | 451篇 |
2021年 | 1059篇 |
2020年 | 654篇 |
2019年 | 1156篇 |
2018年 | 1333篇 |
2017年 | 944篇 |
2016年 | 1099篇 |
2015年 | 1214篇 |
2014年 | 1732篇 |
2013年 | 2529篇 |
2012年 | 3609篇 |
2011年 | 3642篇 |
2010年 | 2049篇 |
2009年 | 1849篇 |
2008年 | 3283篇 |
2007年 | 3358篇 |
2006年 | 3357篇 |
2005年 | 3301篇 |
2004年 | 3128篇 |
2003年 | 2896篇 |
2002年 | 2849篇 |
2001年 | 1796篇 |
2000年 | 1827篇 |
1999年 | 1629篇 |
1998年 | 858篇 |
1997年 | 689篇 |
1996年 | 589篇 |
1995年 | 613篇 |
1994年 | 579篇 |
1993年 | 534篇 |
1992年 | 1257篇 |
1991年 | 1198篇 |
1990年 | 1167篇 |
1989年 | 1074篇 |
1988年 | 1012篇 |
1987年 | 1022篇 |
1986年 | 974篇 |
1985年 | 991篇 |
1984年 | 821篇 |
1983年 | 706篇 |
1982年 | 524篇 |
1981年 | 450篇 |
1980年 | 441篇 |
1979年 | 659篇 |
1978年 | 519篇 |
1977年 | 420篇 |
1976年 | 411篇 |
1974年 | 427篇 |
1973年 | 397篇 |
1972年 | 388篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Background
Exercise has been recommended for improving global-well being in adults with fibromyalgia. However, no meta-analysis has determined the effects of exercise on global well-being using a single instrument and when analyzed separately according to intention-to-treat and per-protocol analyses. The purpose of this study was to fill that gap. 相似文献52.
Deborah P Jones Carlos A Camargo Frank E Speizer R Graham Barr 《The Journal of asthma》2007,44(4):291-295
The authors tested the hypothesis that short stature predicts adult-onset asthma independent of obesity among women in the Nurses' Health Study. Height, weight, and physician-diagnosed asthma were assessed with validated questionnaire items. Proportional hazard models adjusted separately for weight and body mass index. The rate of newly diagnosed asthma was 1.55 times greater in the shortest versus the tallest quintile after adjustment for weight (95% CI, 1.26-1.91). After adjustment for body mass index, the rate ratio was 1.16 (95% CI, 0.94-1.42). Short stature predicted adult-onset asthma in a large cohort of women, but this association was not independent of obesity. 相似文献
53.
Fengxiu Ouyang Binyan Wang Lester M. Arguelles Xiping Xu Jianhua Yang Zhiping Li Liuliu Wang Xue Liu Genfu Tang Houxun Xing Craig Langman Xiaobin Wang 《Archives of osteoporosis》2007,2(1-2):29-43
Summary We prospectively examined bone growth patterns in 894 children aged 6–17 years at the baseline visit, with a 6-year follow-up.
Results show bone “tracking” over a six-year interval and sexual dimorphism of bone attained levels and timing of peak bone
growth. Our findings underscore childhood and adolescence as critical periods for building bone and developing gender differences.
Introduction Bone growth patterns were prospectively examined in 894 Chinese children (496 males), aged 6–17 yrs, from a population-based
twin cohort. Whole-body bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were measured by DEXA at
baseline and a 6-yr follow-up.
Methods Graphic smoothing plots and generalized estimating equations were used to model bone attained levels, growth, and “tracking”.
Results Attained levels of BMC and BA increased curvilinearly with age. Male attained levels were higher than females after age ∼15 yr,
but BMD was lower between 13–17 yrs (Tanner stage I to IV). In both genders, peak BMC and BMD growth lagged ∼2 yrs behind
peak BA growth, which lagged 2 yrs behind peak height growth. Peak bone growth occurred 1–3 yrs later in males. Over the 6-yr
follow-up, all bone measurements “tracked”, but “shifting” across ranks also occurred, and baseline tertile ranking influenced
bone growth. Females with early menarche had higher attained levels than females with late menarche at age 12–13 yrs.
Conclusion Our findings confirm and expand previous studies on peak bone growth conducted in Caucasian cohorts, particularly sexually
dimorphic and maturational effects. The significant “tracking” of bone measurements in this 6-yr follow-up study underscores
the importance that osteoporosis prevention should begin in childhood and adolescence.
Fengxiu Ouyang and Binyan Wang contributed equally to this article.
Source(s) of support: This study is supported in part by grant R01 HD049059, R01 HL0864619 and R01 AR045651 from the National
Institute of Health and by the Food Allergy Project. 相似文献
54.
Charlotte J. Harden Bernard M. Corfe J. Craig Richardson Peter W. Dettmar Jenny R. Paxman 《Nutrition Research》2009
This cross-sectional analysis evaluated the effect of age and body mass index (BMI) on Three-Factor Eating Questionnaire scores in males. Subjects (n = 60) were recruited according to BMI status. Each completed the 51-item Three-Factor Eating Questionnaire. The group was split at the median age to produce a “younger” and “older” group for statistical analysis. A 2-way between-groups analysis of variance revealed a significant main effect of BMI on disinhibition (P = .003) and hunger (P = .041) with higher levels found in overweight males compared to healthy-weight counterparts. A significant main effect of age on hunger (P = .046) demonstrated older males were less susceptible to hunger than younger males. These insights provide a better understanding of eating behavior across the male life cycle and may assist health professionals to better guide men in weight management in the light of rising overweight/obesity. 相似文献
55.
56.
Paul Roderick Ruth Davies Chris Jones Terry Feest Steve Smith Ken Farrington 《Nephrology, dialysis, transplantation》2004,19(3):692-701
BACKGROUND: The demand for renal replacement therapy (RRT) in England has risen steadily, although from a lower base than many other developed countries. Predicting the future demand for RRT and the impact of factors such as the acceptance rate, transplant supply and patient survival, is required in order to inform the planning of such services. METHODS: A discrete event simulation model estimates the future demand for RRT in England in 2010 for a range of scenarios. The model uses current prevalence and current and projected future acceptance rates, survival rates and the transitions between modalities to predict future patient numbers. National population and mortality data, published literature and data from the UK Renal Registry and UK Transplant, are used to estimate unmet need for RRT, the impact of changing demography and incidence of Type 2 diabetes, patient haemodialysis (HD) survival and transplant supply. RESULTS: By 2010 the predicted prevalence will have increased from about 30,000 in 2000 to between 42 and 51,000 (900-1000 p.m.p.), an average annual growth of 4.5-6%. Changing transplant supply has a small effect on overall numbers but changes the proportion of patients with functioning graft by up to 8%. Even with an optimistic increase in transplant supply (11% p.a. for 5 years), numbers on HD will continue to rise substantially, especially in the elderly. The factors most influencing future patient numbers are the acceptance rate and dialysis survival. CONCLUSION: This model predicts a substantial growth in the RRT population to 2010 to a rate approaching 1000 p.m.p., particularly in the elderly and those on HD, with a steady state not being reached for at least 25 years. 相似文献
57.
D Y Jones K W Miller B P Koonsvitsky M L Ebert P Y Lin M B Jones H F DeLuca 《The American journal of clinical nutrition》1991,53(5):1281-1287
The effect of olestra on vitamin D status was assessed in a 6-wk, double-blind, placebo-controlled study involving 202 free-living adults. Subjects consumed a total of 20 g/d of olestra or triglycerides in cookies eaten at each meal. A 20-micrograms ergocalciferol capsule was taken with each morning meal. Serum 25-hydroxyergocalciferol (25-OHD2) concentrations rose from approximately 5.7 to 39.0 and 31.7 nmol/L in the placebo and olestra groups, respectively, at week 6. At week 6, 25-OHD2 contributed 46-54% to total serum 25-OHD concentration compared with 11% at baseline. The 19% decrease in serum 25-OHD2 concentrations produced by olestra in this study is equivalent to a decrease of approximately 1.2 nmol/L under nonsupplemented dietary conditions. Ingesting 20 g olestra/d in the diet is thus not expected to affect vitamin D nutritional status. 相似文献
58.
Richard B Thompson Ewout J van den Bos Bryce H Davis Yoshihisa Morimoto Damian Craig Brad S Sutton Donald D Glower Doris A Taylor 《The Journal of heart and lung transplantation》2005,24(2):205-214
BACKGROUND: Pre-clinical and clinical studies suggest that transplantation of bone marrow-derived stem cells can improve global cardiac function. However, no quantitative assessment of regional systolic contraction and correlation with phenotype has been made. Therefore, we used our model of cryoinfarcted rabbit myocardium for intracardiac transplantation of a mixed population of bone marrow-derived cells and assessed both regional function and myogenic conversion of the cells. METHODS: Nineteen New Zealand white rabbits underwent cryoinjury of the left ventricle. Autologous bone marrow (BM) cells were expanded in vitro. After 2 weeks, either 1 x 10(8) mixed BM-derived progenitor cells (BM group, n = 11) or vehicle (control group, n = 8) were injected into the cryoinjured region. Regional systolic function was measured using micromanometry and sonomicrometry before and 4 weeks after cell injection; cell phenotype was evaluated histologically. RESULTS: All animals in the BM group significantly improved both systolic shortening (0.11 +/- 0.7 vs -0.05 +/- 0.05 mm in the control group, p < 0.05) and regional stroke work when compared with control (9.6 +/- 2.4 vs -1.2 +/- 1.2 mm . mm Hg, p < 0.003). In addition, the BM group had improved global diastolic function, as measured by minimum dP/dt and end-diastolic pressure. On histologic assessment, BM cells differentiated toward a myogenic phenotype. CONCLUSIONS: Transplanting a mixed population of marrow-derived cells that can adopt a myogenic phenotype improves regional contractility and diastolic relaxation after myocardial infarction. 相似文献
59.
Psychiatric morbidity in Hobart's dependent aged 总被引:1,自引:0,他引:1
D W Kay T A Holding B Jones S Littler 《The Australian and New Zealand journal of psychiatry》1987,21(4):463-475
Psychiatric morbidity in the dependent aged was studied in the elderly population of Hobart's nursing homes and long-stay hospitals. Only patients with home addresses in Hobart and who were admitted for the first time aged 70 years or over were included. Three hundred and twelve persons were interviewed with a standard interview, and an informant was interviewed when appropriate. The medical records were searched for diagnoses and drug treatments. Physical disability was rated on an ad hoc scale. Comparisons were made of the prevalence of dementia, depression and anxiety in different types of unit, and between these and two domiciliary samples, one of which received domiciliary nursing services (n = 100) and the other not (n = 100). The differential use of institutions by men and women, and a possible sex difference in the prevalence of dementia is discussed. 相似文献
60.