全文获取类型
收费全文 | 65918篇 |
免费 | 6741篇 |
国内免费 | 102篇 |
专业分类
耳鼻咽喉 | 743篇 |
儿科学 | 2091篇 |
妇产科学 | 1966篇 |
基础医学 | 9918篇 |
口腔科学 | 1367篇 |
临床医学 | 8930篇 |
内科学 | 12061篇 |
皮肤病学 | 874篇 |
神经病学 | 6193篇 |
特种医学 | 1770篇 |
外国民族医学 | 1篇 |
外科学 | 7738篇 |
综合类 | 1162篇 |
一般理论 | 74篇 |
预防医学 | 7551篇 |
眼科学 | 1054篇 |
药学 | 5067篇 |
中国医学 | 88篇 |
肿瘤学 | 4113篇 |
出版年
2022年 | 521篇 |
2021年 | 1081篇 |
2020年 | 746篇 |
2019年 | 1232篇 |
2018年 | 1380篇 |
2017年 | 1032篇 |
2016年 | 1180篇 |
2015年 | 1277篇 |
2014年 | 1798篇 |
2013年 | 2670篇 |
2012年 | 3661篇 |
2011年 | 3785篇 |
2010年 | 2085篇 |
2009年 | 1927篇 |
2008年 | 3211篇 |
2007年 | 3429篇 |
2006年 | 3365篇 |
2005年 | 3235篇 |
2004年 | 3139篇 |
2003年 | 2956篇 |
2002年 | 2897篇 |
2001年 | 1727篇 |
2000年 | 1714篇 |
1999年 | 1528篇 |
1998年 | 836篇 |
1997年 | 694篇 |
1996年 | 570篇 |
1995年 | 602篇 |
1994年 | 539篇 |
1993年 | 532篇 |
1992年 | 1198篇 |
1991年 | 1128篇 |
1990年 | 1094篇 |
1989年 | 1012篇 |
1988年 | 926篇 |
1987年 | 950篇 |
1986年 | 909篇 |
1985年 | 935篇 |
1984年 | 756篇 |
1983年 | 670篇 |
1982年 | 502篇 |
1981年 | 413篇 |
1980年 | 431篇 |
1979年 | 622篇 |
1978年 | 481篇 |
1977年 | 400篇 |
1976年 | 412篇 |
1974年 | 418篇 |
1973年 | 377篇 |
1972年 | 368篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
121.
OBJECTIVES: To evaluate the sensitivity to change of the Endometriosis Health Profile-30 (EHP-30) questionnaire. SETTING: The Women's Center, John Radcliffe Hospital, Oxford. DESIGN: Postal survey to 66 women undergoing conservative surgery for the treatment of endometriosis-associated pain. The EHP-30 and the Short Form-36 (SF-36) were administered 2 weeks before the operation, and 4 months post-operatively. At T2 a transition question was included to evaluate changes in patients health status. To evaluate responsiveness effect sizes, standardised response means, the index of responsiveness and the minimally and clinically important differences were calculated. RESULTS: Forty (66.6%) patients returned the questionnaires at time 1 and 2. Overall less responsive effect size scores were found for the SF-36 (0.1-0.5) compared to the EHP-30 (-0.1-1.1) for all patients who had undergone treatment. Minimally important differences and the index of responsiveness were overall higher for the EHP-30 (0.4-2.0) compared to the SF-36 (0.1-1.0). Change scores for four of the five scales were significantly correlated with women's responses to the transition question. CONCLUSIONS: Results suggest that the EHP-30 is sensitive to change. Its application in clinical trials should prove beneficial in assessing the impact of medical and surgical interventions upon quality of life for women with endometriosis. 相似文献
122.
AIMS: To determine the most appropriate regression models to use when assessing risk factors for severe hypoglycaemia and to investigate the impact of model misspecification and its clinical implications. METHODS: A total of 1229 children with Type 1 diabetes (mean age 11.7 years sd 4.1), of which 605 (49.2%) were males, were studied. Prospective assessment of severe hypoglycaemia (an event leading to loss of consciousness or seizure) was made over the 9-year period, 1992-2001. Patients were seen every 3 months and episodes of hypoglycaemia along with clinical data were recorded. Over 70% of children never experienced a severe hypoglycaemic event. Data were analysed using the Poisson regression, negative binomial, zero-inflated Poisson (ZIP) and zero-inflated negative binomial (ZINB) models. The over-dispersion and likelihood ratio statistics were calculated and the analytical methods compared. RESULTS: The Poisson regression model did not fit the data well. The negative binomial and the zero inflated Poisson and negative binomial models fitted the data better than Poisson. CONCLUSIONS: The commonly used Poisson regression models to analyse hypoglycaemia epidemiology may lead to biased parameter estimates and incorrect determination of risk factors for hypoglycaemia. We recommend the use of the negative binomial or zero inflated models to examine any risk factors associated with severe hypoglycaemia. Careful consideration must be given to the interpretation of hypoglycaemia surveys and their analysis. 相似文献
123.
124.
BACKGROUND: Somatosensory evoked potentials (SSEPs) have long been recognized as an excellent tool for detecting neural and vascular compromise during vascular, neurosurgical and orthopedic procedures. SSEPs have the ability to localize, central versus peripheral, the area of compromise. Many surgeons use only lower-limb SSEP monitoring when performing lumbar spinal surgery. The upper extremities are usually not monitored during such procedures, and monitoring oxygen saturation does not detect neural compromise. PURPOSE: To report that the expanded use of SSEP monitoring during surgery can be beneficial in detecting peripheral ischemia or neural compromise resulting from positioning. STUDY DESIGN: Three case reviews of orthopedic spine surgeries where SSEP monitoring provided early warnings of vascular and neural compression. METHODS: The cases review three different lumbar procedures in which evidence of peripheral ischemia and nerve compression were detected by SSEP monitoring. RESULTS: By the use of upper- and lower-extremity monitoring during lumbar procedures, early detection of ischemia and nerve compression were noted intraoperatively. These changes prompted examination of the patient and repositioning to correct the ischemia or compression. The repositioning in these cases corrected the problem, and no lasting effects were found. CONCLUSIONS: Including SSEP monitoring of the bilateral upper extremities should be considered during lumbar spinal procedures. Such monitoring can be offered for a slightly increased expense and only minimal time delay to place the additional required electrodes by the technician. As a direct result of the early warning of the SSEP monitoring, we were able to avoid potential ischemic injuries and improve patient outcomes. 相似文献
125.
Jennifer Orlet Fisher Diane C Mitchell Helen Smiciklas-Wright Leann Lipps Birch 《Journal of the American Dietetic Association》2002,102(1):58-64
OBJECTIVE: To evaluate parents' fruit and vegetable intake and their use of pressure to eat in child feeding as predictors of their 5-year-old daughters' fruit and vegetable, micronutrient, and fat intakes. SUBJECTS: Data were obtained from 191 non-Hispanic white families with 5-year-old girls. DESIGN: Parent data included reports of pressure in child feeding and their own fruit and vegetable intake. Girls' intakes of fruits and vegetables, selected micronutrients, and fat were the main outcomes of interest. STATISTICAL ANALYSIS: Structural equation modeling was used to test a model describing relationships among parents' fruit and vegetable intake, parents' use of pressure in child feeding, and daughters' fruit and vegetable, micronutrient, and fat intakes. RESULTS: The model provided a good fit to the data, revealing that girls' fruit and vegetable intake was positively related to their parents' reported fruit and vegetable intake. Parents who consumed fewer fruits and vegetables tended to report greater pressure in child feeding and had daughters who consumed fewer fruits and vegetables. Girls' reported fruit and vegetable intakes were positively related to their micronutrient intakes and negatively associated with fat intake. APPLICATIONS/CONCLUSIONS: This research demonstrates that parents' own fruit and vegetable intake may encourage fruit and vegetable intake in their daughters, leading to higher micronutrient intakes and lower dietary fat intakes. Conversely, pressure to eat may discourage fruit and vegetable intake among young girls. 相似文献
126.
Endorectal surface coil MR imaging of prostatic carcinoma with the inversion-recovery sequence 总被引:1,自引:0,他引:1
F Parivar V Rajanayagam V Waluch R T Eto L W Jones B D Ross 《Journal of magnetic resonance imaging : JMRI》1991,1(6):657-664
The value of inversion-recovery (IR) sequences in the diagnosis and staging of prostatic carcinoma with magnetic resonance (MR) imaging was studied. Twenty-six patients with carcinoma of the prostate were imaged at 1.5 T with an endorectal surface coil and with a variety of IR sequences and a set of spin-echo (SE) sequences for comparison. Ex vivo prostate specimens were imaged again at the same field strength. The two images were correlated with histologic sections. Cancer was identified with MR imaging in 96% of patients. Of the tumors more than 4 mm in diameter, 87% were identified on T2-weighted SE images, whereas only 26% were identified on IR images. However, IR images may be more useful in local staging of carcinoma. Gross capsular infiltration was present in only two patients; however, it was detectable (and excluded in five other patients) by means of IR images. It was not detectable on SE images. The high quality of images obtained with the endorectal coil was confirmed. The authors conclude that addition of the IR sequence to MR imaging with the endorectal coil may improve the usefulness of this examination. 相似文献
127.
128.
J C Stevens A S Jones J Lancer E Beckingham 《Journal of medical engineering & technology》1987,11(6):278-281
The determination of nasal airway resistance by the technique of anterior rhinomanometry is made difficult by several factors. Among these are the variability in the breath by breath measurement of airflow and pressure, the effect of under or over breathing, and the ability to produce a smooth transition between inspiration and expiration during which period the measurements are made. To overcome some of these problems a standard procedure has been developed (in our laboratory) for active anterior rhinomanometry. The nasal resistance is calculated from the mean of three sets of three readings with a rest interval between each set. To enable the procedure to be carried out with consistency it has been implemented on a BBC microcomputer. This enables a breathing guide to be provided for the subject, as well as providing a display of each flow pressure curve, a display of the mean curve, plus and minus one standard deviation, and the calculation of left, right and total nasal airway resistance. 相似文献
129.
130.
Smoking habits in insulin-treated diabetics in Nottinghamshire (UK) and clinic-attending diabetics in Nottingham have been analysed. Compared with the general population, the prevalence of current cigarette smoking is significantly less (p less than 0.001) in both diabetic men and women older than 50 years. Fewer diabetic men over 60 years have ever smoked than in the general population (p less than 0.001) but this finding does not apply to diabetic women. While intervention probably plays some part in this lower prevalence, the most likely explanation is the multiplicative effect of both smoking and diabetes to produce high mortality risks. Actuarial analysis of insulin-treated clinic attenders diagnosed after 1970 showed that at most 14% (95% confidence interval [Cl] 9-18%) of the 183 who smoked at diagnosis had given up 5 years later while a minimum of 8% (95% Cl, 6-11%) of the 313 who were non-smokers had started smoking. Information about the patterns of smoking in patients with chronic disease is incomplete and it appears that too little is being done in clinical services which provide long-term management for these patients to either discourage smoking or determine why some patients give up smoking but others do not. 相似文献