全文获取类型
收费全文 | 4524篇 |
免费 | 348篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 137篇 |
妇产科学 | 90篇 |
基础医学 | 653篇 |
口腔科学 | 63篇 |
临床医学 | 834篇 |
内科学 | 740篇 |
皮肤病学 | 26篇 |
神经病学 | 514篇 |
特种医学 | 83篇 |
外科学 | 387篇 |
综合类 | 67篇 |
一般理论 | 1篇 |
预防医学 | 602篇 |
眼科学 | 58篇 |
药学 | 247篇 |
中国医学 | 16篇 |
肿瘤学 | 316篇 |
出版年
2023年 | 26篇 |
2022年 | 64篇 |
2021年 | 74篇 |
2020年 | 68篇 |
2019年 | 77篇 |
2018年 | 106篇 |
2017年 | 77篇 |
2016年 | 79篇 |
2015年 | 77篇 |
2014年 | 112篇 |
2013年 | 214篇 |
2012年 | 257篇 |
2011年 | 295篇 |
2010年 | 161篇 |
2009年 | 125篇 |
2008年 | 251篇 |
2007年 | 306篇 |
2006年 | 274篇 |
2005年 | 285篇 |
2004年 | 247篇 |
2003年 | 262篇 |
2002年 | 247篇 |
2001年 | 45篇 |
2000年 | 44篇 |
1999年 | 47篇 |
1998年 | 56篇 |
1997年 | 59篇 |
1996年 | 32篇 |
1995年 | 43篇 |
1994年 | 47篇 |
1993年 | 33篇 |
1992年 | 33篇 |
1991年 | 29篇 |
1990年 | 34篇 |
1989年 | 31篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 39篇 |
1983年 | 28篇 |
1982年 | 50篇 |
1981年 | 45篇 |
1980年 | 46篇 |
1979年 | 24篇 |
1978年 | 26篇 |
1977年 | 24篇 |
1976年 | 36篇 |
1975年 | 31篇 |
1974年 | 26篇 |
1973年 | 24篇 |
1971年 | 23篇 |
排序方式: 共有4878条查询结果,搜索用时 15 毫秒
11.
12.
The relationship of perceived control over daily uplifts and hassles to depression and restraint was examined in a sample of 140 middle-class sixth graders. Results indicated that greater control over uplifts was associated with better functioning and lower control over hassles with poorer functioning, even after partialing out the respective number of uplifts and hassles reported. Moreover, when directly compared, control over uplifts showed more powerful associations with adaptational outcomes than did control over hassles. In a separate analysis, the number of uplifts over which children reported high control showed opposite relationships to adaptational outcomes than did the number of uplifts over which children reported low control. A different pattern appeared for hassles. Although the number of hassles with low control was associated with poorer functioning, the number of hassles over which children had high control was unrelated to adaptational outcomes. The possibility that control operates somewhat differently for positive and negative events is discussed.This research was supported by a grant to the second author from the Stanford Center for the Study of Families, Children and Youth. The authors are grateful to Rachelle Hacket for data analysis, Tom Gehring for data collection, and Susan Nolen-Hoeksema for critical comments. 相似文献
13.
Pelvic ultrasound is a widely used diagnostic tool and accessto this investigation is not universally available to all generalpractitioners (GPs). The aim of this study was to assess ifGPs working in the United Arab Emirates (UAE) were using pelvicultrasound appropriately by determining the rates of diagnosticyield and referral after the investigation. It was then ascertainedif these results were affected by the post-graduate trainingor gender of the doctor. The subjects were adult females whohad had a pelvic ultrasound ordered by a GP over a 2-month period.A chart review determined the presenting complaint, the completenessof the request form, the result of the ultrasound and subsequentmanagement of the patient. Diagnostic yields and referral rateswere similar to those found in other studies and were unaffectedby the post graduate training or gender of the doctor or theamount of information contained in the request form. This studysupports the premise that GPs can use pelvic ultrasound appropriatelyand should be allowed free access to this investigation. 相似文献
14.
The random amplification of polymorphic DNA (RAPD method), was used to derive fragments of DNA of the coccidial parasiteEimeria tenella for use both as genetic markers and as an aid for the discrimination of different wild-type and attenuated populations. Of
41 arbitrarily chosen 9-to 27-mer primers, 24 yielded useful arrays of fragments following low-stringency annealing conditions
and the resultant profiles were generally very reproducible. One non-variant fragment of 2 kb hybridised to a single chromosome
(number 12) and four variant fragments were identified. These results strongly suggest that the RAPD method may be an extremely
useful tool for studies on various aspects of the genetic organisation of coccidial parasites. 相似文献
15.
Shirley Y. Hill PhD Stuart R. Steinhauer PhD Joseph Zubin PhD Timothy Baughman BA 《Alcoholism, clinical and experimental research》1988,12(4):545-554
One hundred sixty-eight adult siblings and parents from affected and control families were tested for ERP characteristics using two tasks involving an auditory oddball paradigm. Significant within family differences among affected families suggest that risk for developing alcoholism may be seen even in adult subjects who have had experience consuming alcohol. Further, analysis of quantity and recency of drinking in the past seven days were not correlated with either amplitude or latency of P300, suggesting that the within-family differences observed reflect relative risk for developing alcoholism rather than experience with alcohol. 相似文献
16.
Rupert C M Jones Shirley Copper Oksana Riley Frank Dobbs 《The British journal of general practice》2002,52(480):567-568
Pulmonary rehabilitation is an effective intervention for patients with chronic obstructive pulmonary disease (COPD). It is usually available only through selected hospitals. A pilot study was undertaken to see if pulmonary rehabilitation performed by the primary health care team in one practice was feasible. Fourteen patients were recruited; 13 completed the programme and one year of follow-up. The programme was well received by patients and staff. There were not enough suitable patients among a practice list of 10,500 to justify the running of this programme for a single practice; one primary care group would suffice 相似文献
17.
The prognostic impact of fluctuating levels of C-reactive protein in Brazilian haemodialysis patients: a prospective study. 总被引:5,自引:2,他引:3
Marcelo M Nascimento Roberto Pecoits-Filho A Rashid Qureshi Shirley Y Hayashi Roberto C Manfro Maria A Pachaly Luciana Renner Peter Stenvinkel Bengt Lindholm Miguel C Riella 《Nephrology, dialysis, transplantation》2004,19(11):2803-2809
BACKGROUND: A single elevated C-reactive protein (CRP) value predicts mortality in haemodialysis (HD) patients, but the relative importance of repeated vs occasional positive systemic inflammatory response findings is not known. METHODS: To assess the influence on survival of occasional inflammation, CRP, serum albumin (S-Alb) and fibrinogen were analysed bimonthly in 180 HD patients (54% male, 49+/-14 years). Clinically significant inflammation was defined as CRP >5.1 mg/l, based on the receiver operating characteristics curve for CRP as predictor of death. Based on four consecutive measurements of CRP, patients were assigned into three groups: group 1 (n = 74; 41%), no inflammation (CRP < or = 5.1 mg/l in all measurements); group 2 (n = 65; 36%), occasional inflammation (1-3 measurements of CRP > 5.1 mg/l); and group 3 (n = 41; 23%), persistent inflammation (all measurements of CRP >5.1 mg/l). The nutritional status was evaluated by subjective global assessment (SGA) and body mass index (BMI), and the survival (21 months of follow-up) by Kaplan-Meier curve and Cox model. RESULTS: The median and range of CRP values (mg/l) for group 1, 2 and 3 were: 3.2 (3.2-5.1), 3.6 (3.2-54.9) and 13.8 (5.2-82), respectively (P<0.001), whereas the prevalence of malnutrition, assessed by SGA and BMI, did not differ significantly between the groups. The survival rate by Kaplan-Meier analysis was significantly different among the groups (chi2 = 12.34; P = 0.0004). Patients in group 3 showed the highest mortality (34%; P = 0.001), compared with group 1 (8%) and group 2 (14%; P = 0.01), respectively, whereas there was no significant difference in mortality between groups 1 and 2. Age, CRP, S-Alb level and SGA were independent predictors of mortality. CONCLUSION: The patients with a persistent elevation of CRP had a higher mortality rate than the patients with occasional CRP elevation. Thus, persistent, rather than occasional, inflammation is an important predictor of death in HD patients. 相似文献
18.
Arm function after axillary dissection for breast cancer: a pilot study to provide parameter estimates. 总被引:8,自引:0,他引:8
Sixty-three women participated in a study in Calgary, Alberta to assess the rate of arm recovery and factors affecting it up to one year after axillary node dissection for breast cancer. Outcomes included objective measures of swelling, mobility, and strength, and subjective assessments of pain (at rest and with movement) and stiffness. Approximately 42% of women had residual impairment of at least one type one year after surgery, the most common problems being pain (16%) and reduced grip strength (16%). Except for lymphedema, measurements one year after surgery showed little change from measurements at 6 months, suggesting that the shorter follow-up may be appropriate for assessing the long term effects of axillary dissection. Lymphedema was the only sequela which increased over time. The results provide parameter estimates for designing studies to evaluate the role of physiotherapy after axillary dissection. 相似文献
19.
Shirley Kobar Coni C Francis Samantha MaWhinney Teresa Sharp 《Nutrition in clinical practice》2003,18(5):417-421
BACKGROUND: Development of an acclimation protocol for use when measuring resting energy expenditure (REE) would simplify and standardize data collection. The purpose of this study was to determine if our 2 metabolic carts could be used interchangeably and to determine if excluding the first 3 or 5 minutes of data collected as an acclimation period would significantly improve the coefficients of variation (CVs) for oxygen consumed (VO(2)) and carbon dioxide produced (VCO(2)) when performing REE assessments with our metabolic cart systems. METHODS: Thirteen healthy, nonsmoking adults ranging in age from 32 to 45 years, with activity levels ranging from sedentary to highly active, participated. Indirect calorimetry was performed twice in the morning after 30 minutes of supine resting. Subjects had fasted for 12 hours, and did not exercise within the last 24 hours. The system order for testing was randomized for the first measurement. When the first measurement was completed, subjects were crossed over for measurement using a second metabolic cart. RESULTS: The CVs for VO(2) and VCO(2) were significantly lower when excluding the first 3 (VO(2), p = .0005), (VCO(2), p = .0024) or 5 minutes (VO(2), p = .0001, VCO(2), p = .0021) of data compared with no exclusions. No significant differences in CVs between the 3- and 5-minute exclusions were found for VO(2) (p = .3224) or VCO(2) (p = .2255). CONCLUSIONS: Clearly, our machines cannot be used interchangeably within a study. An acclimation period improves CVs of VO(2) and VCO(2.) The similarities in CVs led us to adopt a 3-minute acclimation period for measuring REE. 相似文献
20.