全文获取类型
收费全文 | 4727篇 |
免费 | 391篇 |
国内免费 | 249篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 58篇 |
妇产科学 | 16篇 |
基础医学 | 283篇 |
口腔科学 | 70篇 |
临床医学 | 289篇 |
内科学 | 905篇 |
皮肤病学 | 61篇 |
神经病学 | 391篇 |
特种医学 | 43篇 |
外科学 | 64篇 |
综合类 | 824篇 |
预防医学 | 412篇 |
眼科学 | 25篇 |
药学 | 1099篇 |
中国医学 | 746篇 |
肿瘤学 | 77篇 |
出版年
2023年 | 37篇 |
2022年 | 93篇 |
2021年 | 133篇 |
2020年 | 111篇 |
2019年 | 117篇 |
2018年 | 105篇 |
2017年 | 150篇 |
2016年 | 151篇 |
2015年 | 135篇 |
2014年 | 254篇 |
2013年 | 430篇 |
2012年 | 331篇 |
2011年 | 365篇 |
2010年 | 271篇 |
2009年 | 214篇 |
2008年 | 186篇 |
2007年 | 243篇 |
2006年 | 201篇 |
2005年 | 167篇 |
2004年 | 186篇 |
2003年 | 171篇 |
2002年 | 139篇 |
2001年 | 93篇 |
2000年 | 89篇 |
1999年 | 74篇 |
1998年 | 91篇 |
1997年 | 102篇 |
1996年 | 65篇 |
1995年 | 70篇 |
1994年 | 70篇 |
1993年 | 42篇 |
1992年 | 35篇 |
1991年 | 42篇 |
1990年 | 39篇 |
1989年 | 27篇 |
1988年 | 21篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 44篇 |
1984年 | 31篇 |
1983年 | 27篇 |
1982年 | 41篇 |
1981年 | 23篇 |
1980年 | 25篇 |
1979年 | 14篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 16篇 |
1975年 | 11篇 |
1974年 | 8篇 |
排序方式: 共有5367条查询结果,搜索用时 15 毫秒
1.
This study is focussed on micro-encapsulation of essential oils in polylactic acid (PLA) and a poly(methyl methacrylate) (PMMA) matrix as well as blends of the same. Microspheres were prepared by the solvent evaporation technique and characterised by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infra-red spectroscopy (FTIR). The encapsulation efficiencies and release profiles of the essential oils were studied by gas chromatography mass spectrometry (GC-MS) and head-space solid-phase microextraction GC-MS, respectively. Furthermore, the microspheres were tested for antibacterial activity against both Gram-negative and Gram-positive bacterial strains.
The results showed that the microspheres compositions (PLA/PMMA ratio) have significant effect on their characteristics. The process adopted for preparing the microspheres promoted formation of spherical particles at the sizes of 1.5–9.5?µm. The highest encapsulation efficiency of the prepared microspheres was observed in systems consisting of linalool (81.10?±?10.0?wt. % for PLA system and 76.0?±?3.3?wt. % for PMMA system). Confirmation was also made that the release rate of the microspheres was affected by the size of the same. 相似文献
2.
3.
Improving oral health: current considerations 总被引:1,自引:0,他引:1
S. Ciancio 《Journal of clinical periodontology》2003,30(S5):4-6
4.
5.
6.
7.
兰敏 《四川生殖卫生学院学报》2005,(5):18-21
胡塞尔继承了西方哲学史上的本质主义路线,严格区分事实和本质、形式本质和实质本质,提出了他的现象学本质观。本质观使我们对“本质”的了解获得了从柏拉图主义和洛克主义、实在论和唯名论非此即彼之争中挣脱出来的可能。 相似文献
8.
A. G. Dupont 《European journal of clinical pharmacology》1990,38(Z2):S96-S100
A randomized, double-blind, placebo-controlled study was conducted to study the effects of acute and chronic administration of carvedilol in essential hypertension, with special emphasis on renal haemodynamics and function. Acute administration of a single dose of 50 mg carvedilol reduced systolic and diastolic blood pressure without inducing reflex tachycardia. Renal blood flow was preserved; accordingly, renal vascular resistance was significantly reduced. A significant reduction in the glomerular filtration rate and filtration fraction was observed. Plasma renin activity (PRA) and plasma aldosterone values were not changed. Chronic carvedilol treatment produced a significant fall in systolic and diastolic blood pressure, heart rate, PRA and plasma aldosterone. Renal blood flow, glomerular filtration rate and filtration fraction also remained unchanged; renal vascular resistance decreased significantly. It is concluded that carvedilol possesses definite antihypertensive and renal vasodilating properties, both acutely and after chronic treatment. 相似文献
9.
10.
Martin Tepel 《Nephrology, dialysis, transplantation》2003,18(8):1439-1442
Reactive oxygen species: general aspects Reactive oxygen species, including superoxide radicals, hydrogenperoxide, nitric oxide, peroxynitrite, hydroxyl radicals andhypochlorous acid are by-products of normal metabolic processesin cells. Reactive oxygen species can be found in several cellsincluding macrophages and vascular smooth muscle cells. At lowconcentrations reactive oxygen species can act as physiologicalmediators of cellular responses whereas higher concentrationsmay cause cell damage [1,2]. The major sources of reactive oxygenspecies are leakages from the electron transport chains of mitochondriaand endoplasmic reticulum. Cellular energy metabolism is basedon the production of ATP through the electron transport reactionin which O2 accepts electrons and H+ and then is eventuallyreduced to water. Only 12% of the electrons are leakedto generate superoxide radicals in reactions mediated by coenzymeQ and ubiquinone and its complexes. During ageing (and probablyin patients 相似文献