全文获取类型
收费全文 | 13445篇 |
免费 | 924篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 243篇 |
儿科学 | 368篇 |
妇产科学 | 179篇 |
基础医学 | 1619篇 |
口腔科学 | 285篇 |
临床医学 | 1542篇 |
内科学 | 2969篇 |
皮肤病学 | 229篇 |
神经病学 | 1282篇 |
特种医学 | 638篇 |
外科学 | 2148篇 |
综合类 | 129篇 |
一般理论 | 5篇 |
预防医学 | 940篇 |
眼科学 | 334篇 |
药学 | 755篇 |
中国医学 | 15篇 |
肿瘤学 | 744篇 |
出版年
2023年 | 87篇 |
2022年 | 172篇 |
2021年 | 364篇 |
2020年 | 202篇 |
2019年 | 324篇 |
2018年 | 389篇 |
2017年 | 257篇 |
2016年 | 326篇 |
2015年 | 406篇 |
2014年 | 482篇 |
2013年 | 596篇 |
2012年 | 1014篇 |
2011年 | 980篇 |
2010年 | 578篇 |
2009年 | 476篇 |
2008年 | 860篇 |
2007年 | 845篇 |
2006年 | 806篇 |
2005年 | 747篇 |
2004年 | 602篇 |
2003年 | 581篇 |
2002年 | 477篇 |
2001年 | 184篇 |
2000年 | 159篇 |
1999年 | 205篇 |
1998年 | 113篇 |
1997年 | 110篇 |
1996年 | 79篇 |
1995年 | 69篇 |
1994年 | 67篇 |
1993年 | 50篇 |
1992年 | 100篇 |
1991年 | 109篇 |
1990年 | 97篇 |
1989年 | 106篇 |
1988年 | 92篇 |
1987年 | 88篇 |
1986年 | 84篇 |
1985年 | 102篇 |
1984年 | 87篇 |
1983年 | 57篇 |
1982年 | 62篇 |
1981年 | 54篇 |
1980年 | 64篇 |
1979年 | 83篇 |
1978年 | 56篇 |
1976年 | 42篇 |
1975年 | 46篇 |
1974年 | 43篇 |
1972年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Mary E. Van Bourgondien Lee M. Marcus Eric Schopler 《Journal of autism and developmental disorders》1992,22(4):493-506
The purpose of this study was to clarify the issue of whether DSM-III-R (American Psychological Association [APA], 1987) over-or underdiagnoses autism by comparing this diagnostic system to a well-established objective measure of diagnosis, the Childhood Autism Rating Scale (CARS). A secondary goal was to determine which of the 16 criteria are the best discriminators of autism. DSM-III-R, CARS, and clinical diagnoses of 138 consecutive admissions to a statewide program for the diagnosis and treatment of autistic and related communication-handicapped individuals (Division TEACCH in North Carolina) were compared. Results indicated a generally high degree of agreement on the diagnosis of autism using the three systems. Within this tratment-oriented program, the CARS and clinical ratings diagnosed a greater number of cases as autistic than did the DSM-III-R criteria, suggesting that DSM-III-R slightly underdiagnosed autism. The criteria that most strongly related to the diagnosis of autism regardless of the system were lack of awareness of others, abnormal social play, an impaired ability to make friends, abnormal nonverbal communication, stereotypic body movements, and restricted range of interests. 相似文献
23.
Twenty-nine New Zealand white rabbits were allocated to undergo insertion of either polytetrafluoroethylene (PTFE) (n = 22) or microporous silicone rubber (SR) (n = 7), 3-mm diameter, 10-mm long aortic grafts. Animals with PTFE grafts received aspirin (ASA) 10 mg/kg/d and dipyridamole (DPM) 10 mg/kg/d (n = 11) or placebo (n = 11). Autologous In-111-oxine-labeled platelets were reinfused on reestablishment of blood flow through the graft. Using gamma camera images, an external graft platelet accumulation index (E-GPAI) was calculated as the In-111 activity in the graft area to the reference aorta at 24, 48, and 72 hours post implantation. Mean E-GPAI +/- SEM values for the ASA/DPM (n = 4) and control groups (n = 7) were 1.13 +/- 0.16 and 1.34 +/- 0.05 (NS) at 24 hours, 1.20 +/- 0.16 and 1.33 +/- 0.07 (NS) at 48 hours, and 1.38 +/- 0.07 and 1.35 +/- 0.10 (NS) at 72 hours, respectively. A similar internal graft platelet accumulation index (I-GPAI) was constructed based on In-111 activity in excised grafts and reference aorta measured in a scintillation counter. Mean I-GPAI +/- SEM values for the PTFE ASA/DPM (n = 9) and control groups (n = 8) at 48 hours post implantation were 43.1 +/- 2.7 and 216.8 +/- 73.9 (P = 0.05), respectively. I-GPAI values for the SR grafts were 192.5 +/- 43.1. Conclusion: The E-GPAI was not sensitive enough to demonstrate the effect of antiplatelet medication on platelet accumulation on the PTFE grafts.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
24.
25.
Z H Marcus B Lunenfeld R Weissenberg L M Lewin 《Gynecologic and obstetric investigation》1987,23(1):54-59
Human seminal plasma from normal or patients with abnormal parameters of the ejaculates contains an inhibitory material that expresses potent in vitro inhibitory activity on PHA-M-induced blast transformation and NK activity. Using the test of inhibition of NK activity, the semen samples from individuals with higher concentrations of fructose had higher inhibitory activity. The results described herein suggest that inhibitory activity for blast transformation may be present in the prostatic fluid while the NK inhibition aspects are correlated with the vesicle-marker (fructose). Inhibition of the immune responses by human seminal plasma of the effector functions indicates the interesting implication that soluble factors may indirectly protect against or promote human autoimmune infertility disease. 相似文献
26.
C S Cleeland R K Portenoy M Rue T R Mendoza E Weller R Payne J Kirshner J N Atkins P A Johnson A Marcus 《Annals of oncology》2005,16(6):972-980
BACKGROUND: Cancer pain is highly prevalent and commonly undertreated. This study was designed to determine whether dissemination of a clinical protocol for pain management would improve outcomes in community oncology practices. PATIENTS AND METHODS: A pain management protocol was developed based on accepted guidelines. After baseline assessment, oncology practices were randomly assigned to 'analgesic protocol' (AP) sites, where oncologists implemented the guidelines in a group of lung or prostate cancer patients, or to 'physician discretion' (PD) sites, where customary treatment was continued. Patients treated on protocol and a comparison group of patients with pain due to breast cancer or myeloma were monitored for change in pain using the Brief Pain Inventory, and for change in other symptoms or mood. RESULTS: The protocol terminated early because of poor accrual. We compared groups using proportions of patients who had no or mild pain at follow-up. Although measures of protocol adherence did not suggest the occurrence of major practice change, the proportion of lung or prostate cancer patients with no or mild pain increased significantly from baseline for those treated at AP sites compared with those treated at PD sites. There was no significant difference between the breast and myeloma patients treated at AP sites versus those treated at PD sites. CONCLUSION: A protocol for cancer pain management can improve pain control. Diffusion of these benefits to other patients was not confirmed. Given the small sample size, these findings require confirmation in a larger trial. 相似文献
27.
28.
Molecular characterization of in vivo mutation at the human hypoxanthine phosphoribosyltransferase (hprt) locus has revealed a broad spectrum of mutation, both with regard to germ-line mutation in Lesch-Nyhan and gout patients, and somatic mutation in 6-thioguanine resistant T-lymphocytes from healthy individuals. The pattern of missense mutation shows a non-random distribution with a preferential location to codons for amino acids which are identical in human and the two parasites Schistosoma mansoni and Plasmodium falciparum. Although these 'evolutionary conserved' amino acids account for only 32% of the amino acids in the human hprt protein, they are involved in 76% of the missense mutations at the hprt locus in human T-lymphocytes, 67% in Lesch-Nyhan patients (with severe hprt-deficiency), but only 43% in gout patients (with partial hprt deficiency). This observation supports the notion that evolutionary conserved amino acids constitute functionally important sites in the hprt enzyme, and missense mutations affecting these amino acids will often lead to complete loss of enzyme activity. Substitutions of 'non-conserved' amino acids cause less severe hprt-deficiency (as seen in the gout patients), or may even escape clinical diagnosis. These considerations are important for the understanding of structure-activity relationships in the hprt protein, possible differences between hprt mutational spectra in germ-line and somatic cells, and the mutational spectra induced by specific exogeneous mutagens. 相似文献
29.
30.
Mark D. Rodefeld Mark Ruzmetov Marcus S. Schamberger Donald A. Girod Mark W. Turrentine John W. Brown 《European journal of cardio-thoracic surgery》2005,27(6):949-955
Objective: The infant with a functional single ventricle (SV) and unobstructed pulmonary blood flow (UPBF) requires early protection of the pulmonary vascular bed to ensure suitability for a subsequent Fontan procedure. Systemic obstruction by aortic arch obstruction, subaortic stenosis, or combination of both, has been widely recognized as an important risk factor for poor outcome in children with SV–UPBF who are palliated with pulmonary artery banding (PAB). We reviewed our experience with primary PAB in the subset of patients with SV–UPBF to identify risk factors for subsequent palliative procedures and Fontan completion. Methods: Between January 1990 and May 2004, 80 patients (median age, 14 days) with functional SV and UPBF underwent PAB as their primary palliative procedure. Thirty-five neonates had concomitant aortic coarctation or interrupted aortic arch repair (44%). A Damus–Kaye–Stansel procedure was subsequently performed in 19 patients, and subaortic resection or ventricular septal defect or bulboventricular foramen enlargement was performed in five. Results: There were 4 operative deaths, and 15 late deaths. The actuarial overall survival is 84% at 1 year, 76% at 5 and 15 years. Follow-up is complete in all but six children at a mean interval of 4.9±3.7 years (range, 2 months–15 years). Thirty-seven patients (49%; 37 of 76) have undergone the hemi-Fontan procedure (with three hospital deaths) and 40 patients (53%; 40 of 76; 12 children without previous hemi-Fontan) have undergone the completion Fontan procedure without mortality or Fontan takedown. Conclusion: In infants with single ventricle physiology with or without systemic outflow obstruction and unobstructed pulmonary blood flow, a strategy of pulmonary artery banding carries acceptable operative and mid-term mortality in a high-risk group of patients. Pulmonary artery banding does not compromise performance of subsequent Damus–Kaye–Stansel procedure or completion Fontan palliation. 相似文献