全文获取类型
收费全文 | 42869篇 |
免费 | 3000篇 |
国内免费 | 158篇 |
专业分类
耳鼻咽喉 | 692篇 |
儿科学 | 1115篇 |
妇产科学 | 684篇 |
基础医学 | 5222篇 |
口腔科学 | 653篇 |
临床医学 | 4465篇 |
内科学 | 8477篇 |
皮肤病学 | 616篇 |
神经病学 | 4012篇 |
特种医学 | 1813篇 |
外科学 | 6937篇 |
综合类 | 575篇 |
一般理论 | 47篇 |
预防医学 | 3915篇 |
眼科学 | 987篇 |
药学 | 3020篇 |
中国医学 | 31篇 |
肿瘤学 | 2766篇 |
出版年
2023年 | 256篇 |
2022年 | 285篇 |
2021年 | 1233篇 |
2020年 | 691篇 |
2019年 | 1076篇 |
2018年 | 1282篇 |
2017年 | 893篇 |
2016年 | 921篇 |
2015年 | 1096篇 |
2014年 | 1668篇 |
2013年 | 2202篇 |
2012年 | 3182篇 |
2011年 | 3256篇 |
2010年 | 1741篇 |
2009年 | 1627篇 |
2008年 | 2767篇 |
2007年 | 2719篇 |
2006年 | 2511篇 |
2005年 | 2571篇 |
2004年 | 2454篇 |
2003年 | 2187篇 |
2002年 | 2013篇 |
2001年 | 498篇 |
2000年 | 463篇 |
1999年 | 528篇 |
1998年 | 394篇 |
1997年 | 332篇 |
1996年 | 316篇 |
1995年 | 256篇 |
1994年 | 249篇 |
1993年 | 216篇 |
1992年 | 276篇 |
1991年 | 272篇 |
1990年 | 269篇 |
1989年 | 226篇 |
1988年 | 221篇 |
1987年 | 231篇 |
1986年 | 198篇 |
1985年 | 233篇 |
1984年 | 169篇 |
1983年 | 153篇 |
1982年 | 146篇 |
1981年 | 124篇 |
1980年 | 108篇 |
1979年 | 134篇 |
1978年 | 131篇 |
1977年 | 99篇 |
1976年 | 94篇 |
1974年 | 105篇 |
1973年 | 102篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
American Diabetes Association The initial draft of this paper was prepared by Rebecca G. Schafer MS RD ; Betsy Bohannon MS RD; Marion J. Franz MS RD; Janine Freeman RD; Alberta Holmes MS RD; Sue McLaughlin RD; Linda B. Haas RN; Davida F. Kruger MSN RN; Rodney A. Lorenz MD; Molly M.McMahon MD 《Journal of the American Dietetic Association》1997,97(1):52-53
82.
83.
Williams C. A. Jones H. D. Freeman R. W. Wernke M. J. Williams P. L. Roberts S. M. James R. C. 《Regulatory toxicology and pharmacology : RTP》1994,20(3)
Reference doses (RfDs) and reference concentrations (RfCs) developed by the United States Environmental Protection Agency (USEPA) are typically used in the quantitation of risk of potential adverse human health effects from exposure to environmental chemicals. For a large number of chemicals, however, USEPA RfDs and RfCs have not yet been determined. Thus, for risk assessments that involve a large number of chemicals, there is insufficient toxicity information with which to evaluate potential adverse human health effects for all chemicals present at a particular site. Due to this insufficiency, the risk assessor must either (1) ignore potential exposures on the assumption that omitting these exposures does not significantly alter decisions concerning the remediation of the site or (2) undertake a lengthy and costly analysis to generate the necessary RfDs or RfCs. A potential solution to this problem is to develop estimated permissible concentrations (EPCs), values which represent permissible environmental concentrations or related acceptable daily dosages derived from occupational exposure limits. In the present analysis, acceptable daily dosages determined using the EPC method were compared to USEPA RfDs or RfCs which were converted to dosages based on standard exposure assumptions. Based on a comparative analysis of EPCs and USEPA reference values for 103 chemicals, it was found that EPC daily dosages represent a reasonably conservative surrogate value when USEPA or state reference values are unavailable. Given that there are hundreds of chemicals with occupational exposure limits but no state or USEPA reference values, acceptance of the EPC methodology would provide an interim solution for the problem of insufficient toxicity information for a substantial number of environmental chemical contaminants. 相似文献
84.
85.
86.
Canadian Journal of Anesthesia/Journal canadien d'anesthésie - 相似文献
87.
Christina M Marra Clare L Maxwell Ann C Collier Kevin R Robertson Allison Imrie 《BMC infectious diseases》2007,7(1):37
Background
Cerebrospinal fluid (CSF) pleocytosis may be seen in asymptomatic HIV-infected individuals. This finding complicates interpretation of CSF abnormalities when such individuals are evaluated for other central nervous system infections. The goal of this study was to determine the relationship between CSF pleocytosis, central nervous system (CNS) antiretroviral penetration, adherence to antiretroviral medication regimens, neurological symptoms and performance on neuropsychological tests. 相似文献88.
89.
Robert C Susil Kevin Camphausen Peter Choyke Elliot R McVeigh Gary S Gustafson Holly Ning Robert W Miller Ergin Atalar C Norman Coleman Cynthia Ménard 《Magnetic resonance in medicine》2004,52(3):683-687
A technique for transperineal high-dose-rate (HDR) prostate brachytherapy and needle biopsy in a standard 1.5 T MRI scanner is demonstrated. In each of eight procedures (in four patients with intermediate to high risk localized prostate cancer), four MRI-guided transperineal prostate biopsies were obtained followed by placement of 14-15 hollow transperineal catheters for HDR brachytherapy. Mean needle-placement accuracy was 2.1 mm, 95% of needle-placement errors were less than 4.0 mm, and the maximum needle-placement error was 4.4 mm. In addition to guiding the placement of biopsy needles and brachytherapy catheters, MR images were also used for brachytherapy treatment planning and optimization. Because 1.5 T MR images are directly acquired during the interventional procedure, dependence on deformable registration is reduced and online image quality is maximized. 相似文献
90.