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   47938篇
  免费   2488篇
  国内免费   280篇
耳鼻咽喉   434篇
儿科学   903篇
妇产科学   798篇
基础医学   6110篇
口腔科学   1469篇
临床医学   3104篇
内科学   12420篇
皮肤病学   890篇
神经病学   3929篇
特种医学   2069篇
外科学   7597篇
综合类   180篇
一般理论   1篇
预防医学   1342篇
眼科学   930篇
药学   3103篇
中国医学   101篇
肿瘤学   5326篇
  2023年   290篇
  2022年   593篇
  2021年   1086篇
  2020年   575篇
  2019年   806篇
  2018年   1033篇
  2017年   812篇
  2016年   977篇
  2015年   1019篇
  2014年   1364篇
  2013年   1673篇
  2012年   2687篇
  2011年   3016篇
  2010年   1684篇
  2009年   1501篇
  2008年   2608篇
  2007年   2648篇
  2006年   2621篇
  2005年   2623篇
  2004年   2586篇
  2003年   2401篇
  2002年   2404篇
  2001年   1128篇
  2000年   1082篇
  1999年   1139篇
  1998年   601篇
  1997年   492篇
  1996年   425篇
  1995年   383篇
  1994年   341篇
  1993年   312篇
  1992年   763篇
  1991年   686篇
  1990年   682篇
  1989年   674篇
  1988年   563篇
  1987年   515篇
  1986年   520篇
  1985年   459篇
  1984年   338篇
  1983年   294篇
  1982年   141篇
  1981年   145篇
  1980年   141篇
  1979年   266篇
  1978年   174篇
  1977年   158篇
  1975年   120篇
  1972年   120篇
  1969年   116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
It is not clear that how long the affected fetuses can tolerate fetomaternal hemorrhage (FMH). Incidental serial measurements of the fetal peak systolic velocity of the middle cerebral artery and the retrospective analysis of stocked blood available incidentally indicated that our patient had suffered from FMH for at least 2 weeks prior to delivery.  相似文献   
994.
We evaluated PyroMark Q24 (QIAGEN) pyrosequencing as a method for the identification of mycobacteria, with potential application in clinical practice. Sequence data from the hypervariable region A of the 16S rRNA gene (43 and 35 bp sequences) were obtained using PyroMark Q24, and a similarity search was performed automatically with PyroMark IdentiFire software. Of the 148 mycobacterial type strains tested, 138 (93.2%) were accurately identified to single or clade species level, including complex level. From the remaining 10 strains, 3 (Mycobacterium gilvum, Mycobacterium goodi, and Mycobacterium thermoresistible) showed poor sequencing quality of homopolymers. For 6 other strains (Mycobacterium cosmeticum, Mycobacterium flavescens, Mycobacterium pallens, Mycobacterium hodleri, Mycobacterium xenopi, and Mycobacterium crocinum), the sequences were unreadable from the middle, and Sanger sequencing indicated biallelic site. Finally, a 40 bp sequence for Mycobacterium gordonae could not be obtained despite repeated attempts. PyroMark Q24 provided accurate identification of multiple mycobacterial strains isolated from common clinical settings, but additional gene sequencing is required to distinguish species identified as a group or complex.  相似文献   
995.

Introduction

G protein-coupled receptor 119 (GPR119) is a promising target for the treatment of type 2 diabetes mellitus (T2DM), as both insulin and glucagon-like peptide-1 secretion can be promoted with a single drug. We compared the efficacy and safety of the GPR119 agonist DS-8500a with placebo and sitagliptin 50 mg in Japanese patients with T2DM.

Methods

This randomized, double-blind, parallel-group comparison study was conducted in Japan (trial registration NCT02628392, JapicCTI-153068). Eligible patients aged ≥ 20 years with T2DM and hemoglobin A1c (HbA1c) ≥ 7.0% and < 10.0% were randomized to receive placebo, DS-8500a (25, 50, or 75 mg), or sitagliptin 50 mg once daily for 12 weeks. The primary efficacy endpoint was change in HbA1c from baseline to week 12. Secondary endpoints included change in fasting plasma glucose (FPG), glucose AUC0–3h during a meal tolerance test, 2-hour postprandial glucose (2hr-PPG), and changes in lipid parameters (total, low-density lipoprotein (LDL-) and high-density lipoprotein (HDL-) cholesterol, and triglycerides) at week 12. Safety endpoints included adverse events, hypoglycemia, and clinical/laboratory variables.

Results

DS-8500a demonstrated dose-dependent HbA1c lowering compared with placebo at week 12: change from baseline ? 0.23% (p = 0.0173), ? 0.37% (p = 0.0001), and ? 0.44% (p < 0.0001) in the 25-mg, 50-mg, and 75-mg groups, respectively. At 50- and 75-mg doses, DS-8500a significantly lowered FPG, glucose AUC0–3h, and 2hr-PPG compared with placebo. The glucose-lowering effect was maintained up to 12 weeks. DS-8500a did not lower any of the above parameters to a greater extent than sitagliptin. Compared with placebo and sitagliptin, DS-8500a 50 and 75 mg significantly reduced total cholesterol, LDL-cholesterol, and triglycerides, and significantly increased HDL-cholesterol. All DS-8500a doses were well tolerated. Two cases of clinically relevant drug-related hypoglycemia occurred in the DS-8500a 50-mg group.

Conclusion

DS-8500a was well tolerated and demonstrated significant glucose-lowering effects and favorable changes in lipid profiles up to 12 weeks in Japanese patients with T2DM.

Funding

Daiichi Sankyo Co. Ltd.
  相似文献   
996.
Purpose: Swallowing dysfunction has been reported in Duchenne muscular dystrophy (DMD), but has not been studied in Becker muscular dystrophy (BMD). The aims of this study were to report the characteristics of swallowing dysfunction in BMD compared with DMD.

Materials and methods: The study participants were 18 patients with BMD and 18 patients with DMD. All the patients were examined using videofluorography during swallowing of 5?mL of fluid. The penetration–aspiration scale (P–A scale) and the videofluorographic dysphagia scale (VDS) were used to evaluate dysphagia.

Results: Swinyard functional ability stage was not significantly different between the BMD and DMD groups. Rate of aspiration, P–A scale score, and total VDS score did not differ across groups, but the VDS item score for laryngeal elevation was lower in the BMD group than in the DMD group (median scores 4.5 and 9, respectively; p?r?=?0.78, p?Conclusion: Patients with BMD have swallowing problems similar to those observed in patients with DMD when matched according to physical functional status. These patients should be evaluated and followed-up for the duration of their disease.

  • Implications for rehabiliation
  • Dysphagia is one of the most critical problems in patients with progressive neuromuscular disease but dysphagia in patients with Becker muscular dystrophy (BMD) was not well known.

  • Eighteen patients with BMD and 18 patients with Duchenne muscular dystrophy were examined with videofluorography.

  • Patients with BMD have swallowing problems similar to those observed in patients with DMD.

  相似文献   
997.
998.
ABSTRACT

Purpose: To evaluate the cost-effectiveness for a screening interval longer than 1 year detecting diabetic retinopathy (DR) through the estimation of incremental costs per quality-adjusted life year (QALY) based on the best available clinical data in Japan.

Methods: A Markov model with a probabilistic cohort analysis was framed to calculate incremental costs per QALY gained by implementing a screening program detecting DR in Japan. A 1-year cycle length and population size of 50,000 with a 50-year time horizon (age 40–90 years) was used. Best available clinical data from publications and national surveillance data was used, and a model was designed including current diagnosis and management of DR with corresponding visual outcomes. One-way and probabilistic sensitivity analyses were performed considering uncertainties in the parameters.

Results: In the base-case analysis, the strategy with a screening program resulted in an incremental cost of 5,147 Japanese yen (¥; US$64.6) and incremental effectiveness of 0.0054 QALYs per person screened. The incremental cost-effectiveness ratio was ¥944,981 (US$11,857) per QALY. The simulation suggested that screening would result in a significant reduction in blindness in people aged 40 years or over (?16%). Sensitivity analyses suggested that in order to achieve both reductions in blindness and cost-effectiveness in Japan, the screening program should screen those aged 53–84 years, at intervals of 3 years or less.

Conclusions: An eye screening program in Japan would be cost-effective in detecting DR and preventing blindness from DR, even allowing for the uncertainties in estimates of costs, utility, and current management of DR.  相似文献   
999.
N-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have protective effects against atherosclerosis. Monocyte chemotactic protein (MCP)-1 is a major inflammatory mediator in the progression of atherosclerosis. However, little is known about the regulation of Mcp-1 by DHA and EPA in vessels and vascular smooth muscle cells (VSMCs). In this study, we compared the effect of DHA and EPA on the expression of Mcp-1 in rat arterial strips and rat VSMCs. DHA, but not EPA, suppressed Mcp-1 expression in arterial strips. Furthermore, DHA generated 4-hydroxy hexenal (4-HHE), an end product of n-3 polyunsaturated fatty acids (PUFAs), in arterial strips as measured by liquid chromatography-tandem mass spectrometry. In addition, 4-HHE treatment suppressed Mcp-1 expression in arterial strips, suggesting 4-HHE derived from DHA may be involved in the mechanism of this phenomenon. In contrast, Mcp-1 expression was stimulated by DHA, EPA and 4-HHE through p38 kinase and the Keap1-Nuclear factor erythroid-derived 2-like 2 (Nrf2) pathway in VSMCs. In conclusion, there is a dual effect of n-3 PUFAs on the regulation of Mcp-1 expression. Further study is necessary to elucidate the pathological role of this phenomenon.  相似文献   
1000.
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