全文获取类型
收费全文 | 80418篇 |
免费 | 6133篇 |
国内免费 | 255篇 |
专业分类
耳鼻咽喉 | 913篇 |
儿科学 | 2087篇 |
妇产科学 | 1112篇 |
基础医学 | 10952篇 |
口腔科学 | 859篇 |
临床医学 | 8551篇 |
内科学 | 17289篇 |
皮肤病学 | 892篇 |
神经病学 | 7777篇 |
特种医学 | 3084篇 |
外科学 | 13067篇 |
综合类 | 922篇 |
一般理论 | 94篇 |
预防医学 | 6033篇 |
眼科学 | 1964篇 |
药学 | 5438篇 |
中国医学 | 94篇 |
肿瘤学 | 5678篇 |
出版年
2023年 | 669篇 |
2022年 | 1043篇 |
2021年 | 2423篇 |
2020年 | 1364篇 |
2019年 | 2216篇 |
2018年 | 2539篇 |
2017年 | 1810篇 |
2016年 | 1902篇 |
2015年 | 2225篇 |
2014年 | 3232篇 |
2013年 | 4100篇 |
2012年 | 6555篇 |
2011年 | 6775篇 |
2010年 | 3705篇 |
2009年 | 3258篇 |
2008年 | 5429篇 |
2007年 | 5651篇 |
2006年 | 5216篇 |
2005年 | 5169篇 |
2004年 | 4684篇 |
2003年 | 4296篇 |
2002年 | 3892篇 |
2001年 | 633篇 |
2000年 | 437篇 |
1999年 | 608篇 |
1998年 | 800篇 |
1997年 | 601篇 |
1996年 | 486篇 |
1995年 | 438篇 |
1994年 | 408篇 |
1993年 | 407篇 |
1992年 | 284篇 |
1991年 | 231篇 |
1990年 | 201篇 |
1989年 | 197篇 |
1988年 | 187篇 |
1987年 | 140篇 |
1986年 | 156篇 |
1985年 | 161篇 |
1984年 | 196篇 |
1983年 | 172篇 |
1982年 | 245篇 |
1981年 | 245篇 |
1980年 | 175篇 |
1979年 | 109篇 |
1978年 | 136篇 |
1977年 | 114篇 |
1976年 | 81篇 |
1975年 | 71篇 |
1974年 | 63篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
Survival, mutagenesis, and host cell reactivation in a Chinese hamster ovary cell ERCC1 knock-out mutant 总被引:2,自引:0,他引:2
Rolig Rhonda L.; Layher Susan K.; Santi Barbara; Adair Gerald M.; Gu Feng; Rainbow Andrew J.; Nairn Rodney S. 《Mutagenesis》1997,12(4):277-283
Positive selection-negative selection gene targeting was usedto disrupt the nucleotide excision repair gene ERCC1 in a Chinesehamster ovary cell line, CHO-K1. Southern and Northern analysisshowed that a cell clone isolated by this targeting approach,CHO-7-27, had an ERCC1 gene structure consistent with targeteddisruption of ERCC1 exon V, and did not express ERCC1 mRNA.CHO-7-27 was further characterized with respect to UV and mitomycinC sensitivities, and was shown to exhibit severe mutagen sensitivityphenotypes consistent with those of other CHO cell ERCC1 mutants.Mutation frequency experiments showed that CHO-7-27 was UV-hypermutableat the hypoxanthine-guanine phosphoribosyltransferase locus.Experiments assessing host cell reactivation of viral DNA synthesisfor UV-irradiated adenovirus showed that CHO7-27 exhibited aseverely deficient HCR phenotype similar to that of UV20 cells.Our results demonstrate that CHOK1 cells are hemizygous forthe ERCC1 gene, and show that the comparatively mild mutagensensitivities and lack of severely deficient HCR phenotypesof conventionally derived CHO-K1 ERCC1 mutants, in contrastto the severe phenotypes of CHO-AA8-derived mutants, are notdue to any intrinsic genetic differences between CHO-K1 andCHO-AA8 parental cell lines.
4To whom correspondence should be addressed 相似文献
102.
A. Robert Spitzer Shalom Stahl David Yarnitsky Ernest W. Johnson John R. Wilson R. A. C. Hughes Stefania Morino Giovanni Antonini Kiyotoshi Kaneko Yoji Ohnishi Tetsushi Atsumi Isao Hozumi Tadashi Miyatake Tetsuo Furukawa James P. Knochel Ikuo Mineo Seiichiro Tarui Francis O. Walker Andrew J. Gitter Walter C. Stolov Nicholas J. Capozzoli 《Muscle & nerve》1996,19(4):531-538
103.
K. Hamano Hiroshi Ito Andrew Bushell Kathryn J. Wood Kensuke Esato 《Transplant international》1997,10(4):293-298
In this study, the effect of combining anti-CD4 monoclonal antibody (mAb) and cyclosporin (CyA) therapy at the time of transplantation
was examined. A mouse cardiac allograft model was used. Anti-CD4 mAb administered perioperatively induces long-term survival.
The addition of a short course of CyA given subcutaneously in a regimen of either a high-dose treatment or a standard dose
treatment to the anti-CD4 mAb treatment protocol did not have a detrimental effect on graft survival. Despite having no significant
effect on graft survival, the addition of CyA to the treatment protocol did result in a significant decrease in the level
of IL-2 present in the hearts 7 days after transplantation. The decrease in IL-2 production was directly related to the presence
of CyA in vivo. When CyA treatment was continued throughout the period during which unresponsiveness to the graft is induced
by anti-CD4 mAb therapy, 50 % of the grafted hearts were rejected once the CyA was discontinued. In conclusion, the combined
use of anti-CD4 mAb therapy and CyA did not have a negative effect on graft survival in this model when the two agents were
used concurrently at the time of transplantation.
Received: 2 October 1996 Received after revision: 31 January 1997 Accepted: 5 February 1997 相似文献
104.
105.
P Gough 《Nurse education today》1992,12(2):88-93
This paper aims to place the current changes impacting on nurse education into the wider context of massive organisational and managerial upheaval, at present affecting the entire welfare state. This innovation and structural change is, however, merely an echo of deeper societal processes and the influence of the technological revolution on the private industrial sector and market economy. Within this frame of reference the implications of current reforms for the future organisational form, and management, of colleges of nursing are considered. Concerns are also expressed as to the tenuous control of the professional curriculum. 相似文献
106.
Dr. Andrew G. Bostom M.D. Dr. Anne L. Hume Pharm.D. Dr. Charles B. Eaton M.D. Dr. Joseph P. Laurino Ph.D. Ms. Lisa R. Yanek B.A. Ms. Mary S. Regan B.S. Mr. William H. McQuade M.P.H. Dr. Wendy Y. Craig Ph.D. Ms. Gayle Perrone M.B.A. Dr. Paul F. Jacques Sc.D. 《Pharmacotherapy》1995,15(4):458-464
Study Objective . To determine the efficacy of high-dose ascorbate supplementation in lowering lipoprotein(a) [Lp(a)] levels in patients with premature coronary heart disease (CHD). Design . Randomized, double-blind, placebo-controlled trial. Setting . Outpatient clinic. Patients . Forty-four patients with documented premature CHD. defined as confirmed myocardial infarction and/or angiographically determined stenosis of 50% or greater in at least one major coronary artery before age 60 years. Interventions . Patients were block randomized on the basis of age, gender, and screening Lp(a) concentrations to receive ascorbate 4.5 g/day or placebo for 12 weeks. Measurements and Main Results . High-dose ascorbate was well tolerated and produced a marked elevation in mean plasma ascorbate levels (+1.2 mg/dl; p<0.001). Multiple linear regression analysis revealed no significant effect of supplementation on postintervention Lp(a) levels (p=0.39) in a model that included treatment group assignment, and baseline Lp(a) levels. Conclusions . Our findings do not support a clinically important lowering effect of high-dose ascorbate on plasma Lp(a) in patients with premature CHD. 相似文献
107.
Colonic atresia: current results of treatment 总被引:3,自引:0,他引:3
M Davenport A Bianchi C M Doig D C Gough 《Journal of the Royal College of Surgeons of Edinburgh》1990,35(1):25-28
Eleven cases of colonic atresia presenting in a 13-year period are described. The incidence of this condition is estimated at 1 per 66,000 live births in the north-west of England. A higher incidence of involvement of the transverse colon has been noted in comparison with previously reported cases. Survival was unaffected by the type of surgical procedure, with both primary anastomosis after resection or staged reconstruction after initial colostomy giving excellent results. No deaths occurred in the ten patients subjected to surgical treatment. 相似文献
108.
Andrew G. Sparks Hsi-Han Yeh Siva S. Banda 《Optimal control applications & methods.》1990,11(4):307-325
This paper introduces a design methodology for a dynamic compensator that simultaneously minimizes the upper bound of a quadratic performance index and the H∞-norm of a disturbance transfer function matrix of a multiple-input/multiple-output system whose model contains parameter uncertainty in the state and input matrices. The real parameter uncertainty is modelled as additional measurement outputs and as additional weights on the existing noise inputs and measurement outputs of the system. The compensator equations are derived by taking the dual of a system with parameter variation in the state and output matrices, for which the compensator equations have previously been derived, and then taking the dual of the compensator equations. An algorithm for applying this theory is given and an example is shown. 相似文献
109.
Andrew R. Hoellein MD Christopher A. Feddock MD Charles H. Griffith III MD MSPH John F. Wilson PhD Donald R. Barnett MD MSPH Pat F. Bass III MD MS T. Shawn Caudill MD MSPH 《Journal of general internal medicine》2004,19(5P2):562-565
Due to recent public debate and newly imposed resident work hour restrictions, we decided to investigate the relationship of resident call status to their ambulatory patients' satisfaction. Resident continuity clinic patients were asked to rate their level of satisfaction on a 10-point Likert-type scale. Using multiple regression approaches, these data were then assessed as a function of resident call status. We found that in 646 patient encounters, patient satisfaction scores were significantly less when the resident was postcall, 8.99 ± 1.8, than when not postcall, 9.31 ± 1.3. We herein discuss etiologies and implications of these findings for both patient care and medical education. 相似文献
110.
Use of suture-mediated vascular closure devices for the management of femoral vein access after transcatheter procedures. 总被引:1,自引:0,他引:1
James A Shaw Elizabeth Dewire Alan Nugent Andrew C Eisenhauer 《Catheterization and cardiovascular interventions》2004,63(4):439-443
Groin complications remain the most common complication of cardiac catheterization procedures. While the use of closure devices is increasing for arterial sheaths, venous sheaths tend to be removed and hemostasis achieved with manual compression. We report our experience using Perclose suture-mediated vascular closure device to achieve hemostasis and early mobility in patients who have had venous access as part of their procedure. There were a total of 42 patients (21 males; average age, 63.5 years) studied. The majority of the patients had 7 Fr sheaths (24), with access sites of sheaths up to 14 Fr being closed with this technique. Two patients developed complications at the access site: one patient requiring rehospitalization for intravenous antibiotics because of late access site infection, and one patient with deep venous thrombosis and pulmonary emboli. We conclude that the use of the Perclose suture-mediated closure device for closure of femoral venous access sites is feasible and should be considered especially in patients with larger venous sheaths and those at increased risk of groin complications. 相似文献