首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   26367篇
  免费   1893篇
  国内免费   82篇
耳鼻咽喉   298篇
儿科学   660篇
妇产科学   540篇
基础医学   3585篇
口腔科学   798篇
临床医学   3134篇
内科学   5162篇
皮肤病学   276篇
神经病学   2803篇
特种医学   1017篇
外国民族医学   2篇
外科学   3206篇
综合类   371篇
一般理论   29篇
预防医学   2133篇
眼科学   540篇
药学   2147篇
中国医学   20篇
肿瘤学   1621篇
  2023年   106篇
  2022年   162篇
  2021年   403篇
  2020年   255篇
  2019年   366篇
  2018年   403篇
  2017年   373篇
  2016年   435篇
  2015年   525篇
  2014年   736篇
  2013年   1092篇
  2012年   1649篇
  2011年   1808篇
  2010年   1058篇
  2009年   921篇
  2008年   1737篇
  2007年   1688篇
  2006年   1675篇
  2005年   1788篇
  2004年   1641篇
  2003年   1593篇
  2002年   1484篇
  2001年   350篇
  2000年   289篇
  1999年   344篇
  1998年   388篇
  1997年   294篇
  1996年   286篇
  1995年   268篇
  1994年   216篇
  1993年   196篇
  1992年   199篇
  1991年   183篇
  1990年   181篇
  1989年   181篇
  1988年   180篇
  1987年   167篇
  1986年   175篇
  1985年   178篇
  1984年   192篇
  1983年   181篇
  1982年   217篇
  1981年   184篇
  1980年   190篇
  1979年   123篇
  1978年   133篇
  1977年   124篇
  1976年   95篇
  1975年   109篇
  1974年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
PURPOSE OF REVIEW: Limb length discrepancy and lower extremity angular deformity are among the most common nontraumatic conditions in children for which orthopedic referral is sought. There are a number of developments in the surgical management of these problems which have facilitated and improved the quality of care of affected individuals. RECENT FINDINGS: In recent years, we have developed an improved understanding of ramifications of limb length discrepancy on gait. New treatment options for both limb length discrepancy and deformity include the method of 'guided growth' using small, extraphyseal plates. External fixator technology continues to improve, allowing correction of limb length discrepancy and angular and rotational deformities simultaneously. SUMMARY: The development of these techniques for the treatment of limb length discrepancy and angular deformity has expanded the indications for surgical management and decreased the incidence and severity of potential complications.  相似文献   
993.
994.
The genomic region encompassing complement factor H (CFH) is thought to be important in determining susceptibility to inflammatory diseases such as age-related macular degeneration, but only limited polymorphism has been described. After applying the genomic matching technique to three-generation families and an ethnically diverse reference panel we have demonstrated that the polymorphism resembles that found in the major histocompatibility complex. The different ancestral haplotypes carry either T or C at T1277C but also other more polymorphic alleles over a region of 2 Mb. Thus the association between age-related macular degeneration and T1277 or Y402 actually reflects multiple linked polymorphisms including an indel that cannot be dissected from any direct effect of Y402 and may be more important. We show for the first time that simple algorithms can identify genomic sequence elements that appear to be more useful haplospecific markers than single nucleotide polymorphism or microsatellites.  相似文献   
995.
El-Ansary D, Waddington G, Adams R. Control of separation in sternal instability by supportive devices: a comparison of an adjustable fastening brace, compression garment and sports tape.

Objective

To evaluate the effectiveness of 3 supportive devices in controlling sternal separation.

Design

A cross-sectional, randomized intervention study.

Setting

Participants were from the general community who were referred to the study by their cardiac surgeon or cardiologist.

Participants

Fifteen patients (12 men, 3 women) between 49 and 80 years of age with sternal instability after a median sternotomy.

Interventions

Not applicable.

Main Outcome Measures

Support from sports tape, a compression garment, and an adjustable fastening brace was assessed by an ultrasound-based measure of sternal separation contingent on movement and by self-report measures of comfort, pain, feeling of support, ease of upper-limb movement, and ease of breathing.

Results

For both sternal separation and self-report data, some support was better than no support, and a supportive device worn on the body was better than sports tape. Wearing an adjustable fastening brace was better than a compression garment and, compared with no support, closed the sternal gap by 20% or 2.7mm (95% confidence interval, 1.5-3.9mm). The effects of wearing the different supportive devices on visual analog scale ratings of comfort, pain, support, ease of breathing, and movement mirrored the results obtained for sternal separation, thus providing agreement between self-report and objective measures.

Conclusions

Supportive devices may be useful in the management of patients with sternal instability because wearing one resulted in a reduction of both sternal separation and pain report after movement. The largest effect was obtained from wearing an adjustable fastening brace.  相似文献   
996.
997.
OBJECTIVE: A prospective subgroup analysis of the TAME (Treat A Migraine Early) studies examined the efficacy of rizatriptan in patients treating a menstrual migraine attack. METHODS: Both TAME studies were randomized, placebo-controlled, and double-blind. Adults with migraine were assigned (2:1) to either rizatriptan 10-mg tablet or placebo. Patients were instructed to treat within 1 hour of migraine onset and when the pain was mild. The primary endpoint was 2-hour pain freedom. The diagnosis of menstrual migraine was established according to the revised 2004 International Headache Society (IHS) diagnostic criteria. Data from both studies were pooled for logistic regression analyses. A test for interaction was performed to compare rates of 2-hour pain freedom between patients treating a menstrual and non-menstrual attack. RESULTS: A total of 94 patients (63 in the rizatriptan group and 31 in the placebo group) met IHS criteria for menstrual migraine and treated a menstrual attack. The percentage of patients reporting 2-hour pain freedom was significantly greater for rizatriptan than for placebo (63.5% vs 29.0%; odds ratio = 4.5; 95% confidence interval: 1.7, 11.9; P = .002) in those treating a menstrual attack. In those treating with rizatriptan, the percentage of patients with 2-hour pain freedom did not statistically differ between those treating a menstrual or non-menstrual migraine attack (63.5% vs 57.5%; P = .454). CONCLUSION: Rizatriptan 10 mg was effective for the treatment of menstrual migraine in an early intervention model, as measured by 2-hour pain freedom. Rates of 2-hour pain freedom were comparable for patients treating menstrual and non-menstrual migraine attacks with rizatriptan.  相似文献   
998.
BACKGROUND: The worldwide shortage of registered nurses [Buchan, J., Calman, L., 2004. The Global Shortage of Registered Nurses: An Overview of Issues And Actions. International Council of Nurses, Geneva] points to the need for initiatives which increase access to the profession, in particular, to those sections of the population who traditionally do not enter nursing. This paper reports findings on the costs associated with one such initiative, the British National Health Service (NHS) Cadet Scheme, designed to provide a mechanism for entry into nurse training for young people without conventional academic qualifications. The paper illustrates an approach to costing work-based learning interventions which offsets the value attributed to trainees' work against their training costs. OBJECTIVE: To provide a preliminary evaluation of the cost of the NHS Cadet Scheme initiative. DATA SOURCE: Questionnaire survey of the leaders of all cadet schemes in England (n=62, 100% response) in December 2002 to collect financial information and data on progression of cadets through the scheme, and a follow-up questionnaire survey of the same scheme leaders to improve the quality of information, which was completed in January 2004 (n=56, 59% response). PRINCIPAL FINDINGS: The mean cost of producing a cadet to progress successfully through the scheme and onto a pre-registration nursing programme depends substantially on the value of their contribution to healthcare work during training and the progression rate of students through the scheme. The findings from this evaluation suggest that these factors varied very widely across the 62 schemes. Established schemes have, on average, lower attrition and higher progression rates than more recently established schemes. Using these rates, we estimate that on maturity, a cadet scheme will progress approximately 60% of students into pre-registration nurse training. CONCLUSIONS: As comparative information was not available from similar initiatives that provide access to nurse training, it was not possible to calculate the cost effectiveness of NHS Cadet Schemes. However, this study does show that those cadet schemes which have the potential to offer better value for money, are those where the progression rates are good and where the practical training of cadets is organised such that cadets meet the needs of patients which might otherwise have to be met by non-professionally qualified staff.  相似文献   
999.
1000.
Stable performance between-runs are essential in longitudinal studies and when different studies are being compared. However, changes in analytical kits and laboratory material occur and have the potential to threaten analytical stability. In the present case, we examined how salivary cortisol measurements in our laboratory were affected by: 1) changes in the tampon material and 2) changes in the antibody of the analytical kit. In study 1, saliva from healthy subjects (n = 19) was split and spiked to Salivette polyester and cotton tampons, respectively, and treated as ordinary samples before being analysed for cortisol using a Spectria RIA kit for cortisol. In study 2, 68 anonymous saliva samples were analysed with the Spectria Cortisol RIA kit both before and after the manufacturer changed the antibody. The change from polyester to cotton tampons reduced the measured concentration of salivary cortisol by 62 %. A difference of 12 % between the two runs with different antibodies could not be attributed to differences in storage or in thawing and freezing of samples. To conclude, both a change in the material of the Salivette used for collecting saliva samples as well as a change of antibody in a kit can have a major impact on measurements, as illustrated here for concentrations of cortisol in saliva. It is therefore recommended always to check that the analysis stays in statistical control in one's own laboratory when changes are made, even if the manufacturer reports that the changes should have no effects.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号