全文获取类型
收费全文 | 209235篇 |
免费 | 18168篇 |
国内免费 | 4492篇 |
专业分类
耳鼻咽喉 | 3262篇 |
儿科学 | 4074篇 |
妇产科学 | 3564篇 |
基础医学 | 16568篇 |
口腔科学 | 7187篇 |
临床医学 | 19264篇 |
内科学 | 19979篇 |
皮肤病学 | 2392篇 |
神经病学 | 10275篇 |
特种医学 | 5788篇 |
外国民族医学 | 11篇 |
外科学 | 20400篇 |
综合类 | 33296篇 |
现状与发展 | 9篇 |
一般理论 | 24篇 |
预防医学 | 28414篇 |
眼科学 | 1989篇 |
药学 | 20141篇 |
342篇 | |
中国医学 | 25892篇 |
肿瘤学 | 9024篇 |
出版年
2024年 | 948篇 |
2023年 | 4203篇 |
2022年 | 7891篇 |
2021年 | 10377篇 |
2020年 | 10142篇 |
2019年 | 11412篇 |
2018年 | 10088篇 |
2017年 | 8651篇 |
2016年 | 7694篇 |
2015年 | 7161篇 |
2014年 | 14094篇 |
2013年 | 14330篇 |
2012年 | 12619篇 |
2011年 | 13495篇 |
2010年 | 10866篇 |
2009年 | 9376篇 |
2008年 | 8687篇 |
2007年 | 8774篇 |
2006年 | 7450篇 |
2005年 | 6310篇 |
2004年 | 5230篇 |
2003年 | 4659篇 |
2002年 | 3600篇 |
2001年 | 2976篇 |
2000年 | 2651篇 |
1999年 | 2165篇 |
1998年 | 1723篇 |
1997年 | 1547篇 |
1996年 | 1250篇 |
1995年 | 1195篇 |
1994年 | 1090篇 |
1993年 | 967篇 |
1992年 | 877篇 |
1991年 | 806篇 |
1990年 | 705篇 |
1989年 | 683篇 |
1988年 | 631篇 |
1987年 | 569篇 |
1986年 | 522篇 |
1985年 | 1778篇 |
1984年 | 2051篇 |
1983年 | 1287篇 |
1982年 | 1706篇 |
1981年 | 1180篇 |
1980年 | 1010篇 |
1979年 | 902篇 |
1978年 | 736篇 |
1977年 | 552篇 |
1976年 | 693篇 |
1975年 | 477篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
The in vitro permeabilities of Caco-2 monolayers and permeabilities in tissue sections from colon of monkey, rabbit, and dog were compared using a series of compounds. The selected compounds differed in their physicochemical properties, such as octanol/water partition coefficient, water solubility, and molecular weight. Their structure included steroids, carboxylic acids, xanthins, alcohols, and polyethylene glycols. A linear permeability relationship was established between Caco-2 and colon tissue from both rabbit and monkey. The results suggest that Caco-2 is twice as permeable as rabbit and five times as permeable as monkey colon. However, no clear relationship could be established between Caco-2 monolayers and dog colon permeability. A relationship between permeability in Caco-2 monolayers and human absorption was found. The results suggest that within certain limits, permeability of Caco-2 monolayers may be used as a predictive tool to estimate human drug absorption. 相似文献
62.
Hiroshi Ujike Kazuo Tsuchida Kazufumi Akiyama Yutaka Fujiwara Shigetoshi Kuroda 《Pharmacology, biochemistry, and behavior》1995,50(4):613-617
The ontogeny of the behavioral effects of acute cocaine administration and behavioral sensitization to cocaine in rat pups was investigated. Acute behavior stimulating effects of cocaine were observed in pups as young as 7 postnatal days (PND) old, although they needed a higher dose of cocaine than adult rats to evoke the same motor effects. An adult dose-response curve pattern of stereotypy and locomotion to acute cocaine treatment was observed at PND 21, and of rearing at PND 28. Rats aged PND 7, 14, 21, 28, and 56 received repeated injections of saline or cocaine (15 mg/kg) twice a day for 5 consecutive days. After a 3-week period of abstinence, sensitization to a challenge dose of cocaine was assessed. Cocaine-induced stereotyped behavior was enhanced significantly only in rats in which cocaine pretreatment was initiated on PND 21, 28, and 56, but not earlier on PND 7 and 14. Adult female rats given repeated cocaine injections on PND 56–60 showed significantly greater sensitization than males, but no such sex difference was observed in pups given cocaine repeatedly on PND 21–25 or 28–32. These results show clearly that cocaine-induced behavioral sensitization in rats occurred only when subchronic cocaine administration was commenced on PND 21 or later. 相似文献
63.
PAUL CHRISTINE L.; SANSON-FISHER ROBERT W.; REDMAN SELINA; CARTER SUSAN 《Health promotion international》1994,9(4):241-248
Accidental injury in the home is a major cause of death andill-health among young children. Reducing home safety hazardsby the use of safety devices such as stair barriers and safetytaps has the potential to prevent home injuries. Little is knownabout levels of home safety hazards or how to encourage parentsto reduce hazards. The Safe Place Project examined parents'knowledge of home safety and the prevalence of safety hazardsin homes where there were young children. The study also evaluatedthe effectiveness of a low-cost strategy aimed at reducing homesafety hazards. The strategy used trained volunteers to providehome safety checks and tailored safety education in conjunctionwith increasing the availability of home safety devices. Onehundred and six families with young children participated inthe project. Some homes contained many hazards, with 43% ofthe sample having more than 10 home safety hazards. At follow-up,the intervention group showed a significant reduction in homehazards and a trend towards an increase in knowledge of homesafety. 相似文献
64.
Christopher J. Holmgren Esmonde F. Corbet L. P. Lim 《Community dentistry and oral epidemiology》1994,22(5):396-402
Abstract The aim of this study was to describe the periodontal conditions in 372 35–44-yr-old and 537 noninstitutionalized 65–74-yr-old Hong Kong Chinese who were examined clinically for loss of attachment, recession, probing depth, calculus, and bleeding after probing. Community Periodontal Index (CPI) data and treatment need indications were compiled from index teeth or their substitutes. The prevalence of loss of attachment varied considerably in both cohorts according to the definition of the threshold (≥6, ≥9, and ≥12 mm, respectively). The mean numbers of teeth with loss of attachment at the ≥6-mm threshold and at higher thresholds were small. In both age cohorts, about one-fifth of subjects had probing depths ≥6-mm, while al the ≥9-mm threshold only 2–3% were so affected. Although recession was an important component of loss of attachment in the younger cohort, in the older cohort the prevalence and extent of recession were greater than for probing depths at thresholds ≥4 mm. All subjects had one or more teeth with calculus, bleeding, or both, most teeth being so affected. Eighty-four of the 537 65–74-yr-old subjects were excluded either because of edentulousness or because extractions indicated for the remaining teeth would have rendered the subjects edentulous. The distribution of subjects according to their highest CPI score was remarkably similar for the two cohorts. No subjects in either age group were assessed as “healthy” (CPI code 0) or had “bleeding only” (code 1) as their highest score. While most subjects scored CPI code 2 or 3 us their highest score, only 17% of the younger and 15% of the older cohort scored Community Periodontal Index of Treatment Needs (CPITN) code 4. Differences in the mean number of sextants affected by CPI codes between the two cohorts were mainly due to a greater number of excluded sextants in the older cohort. CPI findings for 35–44-yr-olds differed little from those reported in 1984. 相似文献
65.
整体护理改善护患关系的体会 总被引:2,自引:2,他引:0
整体护理的实施,重塑了护士的职业价值观,增加了护患之间的接触。护士能够在自己的专业范围内积极主动地解决病人的问题,挖掘了护理人员的自身潜力,加深了护患交流,使护患关系明显改善。 相似文献
66.
Mario González-Ulloa 《Aesthetic plastic surgery》1990,14(1):53-57
The author describes his surgical approach to the problems of the aging upper arm and elbow region. Surgery at an appropriate age can prevent the progressive wrinkling of the elbow which is further aggravated by aging of the upper arm. The author's operation is aimed at correcting both portions of the arm anatomy at the same time. 相似文献
67.
Paul R. Finley R. Jane Williams Carla Fletcher 《Journal of clinical laboratory analysis》1988,2(4):249-255
We have devised assays to detect both circulating alloantibodies to platelets (indirect assay) and platelet-association IgG and IgM (direct assay) using a flow cytometric technique. A variety of patients with immune thrombocytopenia were studied. Employment of a confocal lens in the flow cytometer increased the discrimination power of the instrument. Patients with autoimmune thrombocytopenia (idiopathic thrombocytic purpura [ITP], systemic lupus erythematosus (SLE), lymphoma, leukemia, and drug-induced thrombocytopenia showed a significant increase in platelet-associated antibody. Circulating antibodies to platelets (alloantibodies) were demonstrated in cases of platelet refractoriness and neonatal isoimmune purpura. Day-today precision of the assays ranged from 3% to 6% (coefficient of variation). No interference was shown in the presence of hemoglobin (5 g/L), triglycerides (10 g/L), or polyclonal and monoclonal immunoglobulinemia (50 g/L: IgG, IgA, IgM). The sensitivity of the direct assay was 500 attograms of IgG or IgM platelet. 相似文献
68.
John T. Pardeck 《Early child development and care》1990,57(1):23-30
The United States is one of the few economically developed nations without a national policy supporting children and their families. This paper suggests that the United States has a unique national ideology, based on the “Calvinistic Ethic,” which results in opposition to not only social programs for children and families, but to all government supported welfare programs. Such an ethic is not found in European countries. Finally, since the United States does not have a national family policy, millions of children and their families go without health care, lack social services, and suffer from inadequate economic supports. 相似文献
69.
本文在分析黑龙江省妇幼保健机构设置现状的基础上,论述了在社会主义市场经济新形势下,妇幼保健机构发展的指导思想、模式与对策。 相似文献
70.
Mariana Diniz Bisi Santos Arthur Braga Pfeifer Marcos Rogério Pupo Silva Claudio Luiz Sendyk WIlson Roberto Sendyk 《Journal of applied oral science : revista FOB》2007,15(2):148-151
One of the causes of implant failures in cemented implant-retained prostheses is the fracture of abutment screw or UCLA abutment. This article reports a case of simultaneous fracture of two UCLA abutments screws occurring in an implant-supported prosthesis placed in the mandibular molar region. The fractured structures were examined under scanning electron microscopy to investigate the probable causes of the failure, which were not related to failures on materials or fabrication of the screws, but rather were due to shear forces. The misfit in cemented prostheses may be the most likely cause of shear force generation. 相似文献