全文获取类型
收费全文 | 2202篇 |
免费 | 180篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 66篇 |
妇产科学 | 19篇 |
基础医学 | 240篇 |
口腔科学 | 17篇 |
临床医学 | 208篇 |
内科学 | 431篇 |
皮肤病学 | 62篇 |
神经病学 | 148篇 |
特种医学 | 58篇 |
外科学 | 148篇 |
综合类 | 174篇 |
一般理论 | 1篇 |
预防医学 | 278篇 |
眼科学 | 58篇 |
药学 | 361篇 |
1篇 | |
中国医学 | 77篇 |
肿瘤学 | 69篇 |
出版年
2023年 | 46篇 |
2022年 | 77篇 |
2021年 | 81篇 |
2020年 | 69篇 |
2019年 | 93篇 |
2018年 | 101篇 |
2017年 | 67篇 |
2016年 | 73篇 |
2015年 | 70篇 |
2014年 | 148篇 |
2013年 | 160篇 |
2012年 | 112篇 |
2011年 | 128篇 |
2010年 | 105篇 |
2009年 | 95篇 |
2008年 | 111篇 |
2007年 | 96篇 |
2006年 | 70篇 |
2005年 | 66篇 |
2004年 | 76篇 |
2003年 | 52篇 |
2002年 | 66篇 |
2001年 | 45篇 |
2000年 | 40篇 |
1999年 | 36篇 |
1998年 | 20篇 |
1997年 | 30篇 |
1996年 | 22篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 14篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 18篇 |
1978年 | 10篇 |
1977年 | 15篇 |
1976年 | 8篇 |
1975年 | 13篇 |
1974年 | 11篇 |
排序方式: 共有2421条查询结果,搜索用时 15 毫秒
991.
992.
Epidemiology of rickettsial diseases 总被引:4,自引:0,他引:4
Rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. For the spotted fever group (SFG) rickettsiae, Rickettsia typhi. R. tsutsugamushi, Coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. All rickettsioses exist as zoonoses. Moreover, all rickettsiae are found in infected arthopods, which generally serve as the natural hosts and can transmit the infection to the next generation of ticks, mites, chiggers, or fleas. From our anthropocentric viewpoint, Q fever aerosol infection from parturient animals and Brill-Zinsser disease ignited epidemics of louse-borne epidemic typhus are exceptions. However, silent cycles of C. burnetii in ticks and R. prowazekii in the flying squirrel flea may have maintained these agents in transovarial or enzootic cycles for eons before humans and their domestic animals arrived on the scene. Thus, the epidemiology of rickettsial diseases must be recognized as an unfortunate aberration of the rickettsial economy.Several excellent reviews of rickettsial ecology contain a wealth of useful information (2, 8, 55, 70, 84).Presented at the 4th International Symposium on Riskettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990. 相似文献
993.
D. Raoult 《European journal of epidemiology》1991,7(3):276-281
The author reviews the recent advances in the treatment of Mediterranean Spotted Fever and Q fever. In mediterranean spotted fever (M.S.F.), in vitro and preliminary in vivo data support the place of quinolones and josamycin in the treatment of M.S.F. In children josamycin could become the first choice drug as well as in pregnant woman. In Q fever chronic disease should be treated using a combination of antibiotic (doxycycline + quinolones) for a minimum of 3 years.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Disease, Pietany, C.S.F.R., 1–6 October, 1990. 相似文献
994.
Elham Abdollahi Fataneh Tavasolian Amir Abbas Momtazi-Borojeni Morteza Samadi 《Journal of immunotoxicology》2016,13(3):286-300
Interleukin-23 (IL-23) is a regulator of cellular immune responses involved in controlling infection and autoimmune diseases. Strong evidence has shown that IL-23 plays a role in the maintenance of immune responses by influencing the proliferation and survival of IL-17-producing T-helper (TH)-17 cells. The critical role of the IL-23/TH17 axis in immune-mediated diseases has emerged from different studies. It has also been seen that polymorphisms in the IL-23 receptor (IL-23R) gene might influence IL-23 responses. Interestingly, a functional single nucleotide polymorphism (SNP) in the IL-23 receptor gene (IL-23R; rs11209026, 1142 G wild-type A reduced function, Arg381Gln, R381Q) seems to confer a measure of protection against development of inflammatory bowel disease (IBD; Crohn’s disease, ulcerative colitis), ankylosing spondylitis, rheumatoid arthritis, psoriasis, thyroiditis, recurrent spontaneous abortion and asthma, suggesting that a perturbation in the IL-23 signaling pathway is likely to be relevant to the pathophysiology of these diseases. The aim of this review was to provide an evaluation of what is currently known about the protective role of R381Q variant in IL-23R gene in immune-based diseases. 相似文献
995.
目的 建立利用电感耦合等离子体质谱法(ICP-MS)同时测定盐酸溴己新葡萄糖注射液中29种元素杂质含量的分析方法。方法 自2022年9—10月,采用ICP-MS法。样品直接稀释后分析,通过在线加入内标元素来校正测量结果。内标液添加异丙醇进行基质匹配以减少仪器信号漂移干扰和样品基体效应。射频功率1 550 W;雾化气流量1.05 L/min;辅助气流量0.90 L/min;KED模式;碰撞气流量4.5 mL/min;全定量法采集。结果 29个元素在各自的检测浓度范围内线性关系良好(r>0.998 7)。检测限为0.000 057 3~0.285μg/L,平均回收率为91.0%~108.4%(n=3),重复性为1.3%~7.2%(n=6)。结论 该方法快速、准确、操作简便,可用于盐酸溴己新葡萄糖注射液中元素杂质的质量控制。 相似文献
996.
997.
Lam CK Chen J Cao Y Yang L Wong YM Yeung SY Yao X Huang Y Chen ZY 《Atherosclerosis》2008,198(1):85-93
We investigated the relative hypocholesterolemic activity of linoleic acid (LA), conjugated linoleic acid (CLA), -linolenic acid (LN) and conjugated linolenic acid (CLN) in hamsters. Five groups of hamsters (n = 10 each) were fed either the control diet or one of the four fatty acids-supplemented diets for 6 weeks. Results demonstrated that the four octadecaenoic acids decreased plasma cholesterol differently, with CLA being the most effective. Western blotting and RT-PCR analysis demonstrated that the four octadecaenoic acids had no effect on sterol regulatory element binding protein-2 (SREBP-2), liver X receptor (LXR), 3-hydroxy-3-methylglutary-CoA reductase (HMGR), LDL receptor (LDLR), and cholesterol-7-hydroxylase (CYP7A1). However, the four octadecaenoic acids increased the excretion of fecal neutral sterols with CLA being most effective followed by LN, LA and CLN, suggesting they all differentially affect cholesterol absorption. Dietary CLA was associated with the least intestinal acyl coenzyme A: cholesterol acyltransferase (ACAT) activity followed by LN, LA and CLN in a decreasing trend. Since esterification of cholesterol is catalyzed by intestinal ACAT, and is a rate-limiting step in cholesterol absorption, it was concluded that the varying effects of CLA, LN, LA and CLN on blood cholesterol were mediated, at least in part, by their inhibition on intestinal ACAT activity. 相似文献
998.
999.
1000.
INTRODUCTION: Pretest probability assessment and objective testing are combined to appropriately manage patients with suspected pulmonary embolism (PE). However, the interobserver reliability of pretest probability assessment has not been investigated. We sought to determine (for patients with suspected PE) the interobserver reliability of pretest probability assessment (by overall impression (gestalt) versus an explicit clinical model). MATERIALS AND METHODS: A prospective cohort study was conducted at an urban university hospital. For patients referred for ventilation and perfusion (V/Q) scanning for suspected PE, structured assessments (11 history and 4 physical examination parameters) were performed by a referring physician and a designated thrombosis physician. The referring and thrombosis physicians also assigned a pretest probability for PE (low, moderate, or high) by gestalt. An explicit seven-point clinical model for suspected PE was later applied to each structured assessment to determine the pretest probability. Assessments were performed independently and prior to diagnostic test results. Interobserver reliability (two rater unweighted Kappa (kappa) statistic) was determined for each parameter on the structured assessment and the pretest probability assessments (gestalt vs. explicit clinical model). RESULTS: One hundred and ten patients with suspected PE received duplicate assessments. Historical features demonstrated substantial to almost perfect interobserver reliability (kappa=0.60-0.95). For the physical findings, only heart rate had substantial interobserver reliability (kappa=0.60). Pretest probability assessment was not reliable when using physician's gestalt (kappa=0.33), but produced substantial interobserver reliability using the explicit clinical model (kappa=0.62). CONCLUSIONS: Given the inadequate interobserver reliability of pretest probability assessment by overall impression (or gestalt), physicians should use explicit clinical models in the diagnostic management of patients with suspected pulmonary embolism. 相似文献