全文获取类型
收费全文 | 4661篇 |
免费 | 412篇 |
国内免费 | 261篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 86篇 |
妇产科学 | 25篇 |
基础医学 | 1019篇 |
口腔科学 | 40篇 |
临床医学 | 268篇 |
内科学 | 469篇 |
皮肤病学 | 74篇 |
神经病学 | 228篇 |
特种医学 | 59篇 |
外科学 | 368篇 |
综合类 | 539篇 |
预防医学 | 340篇 |
眼科学 | 63篇 |
药学 | 648篇 |
中国医学 | 1027篇 |
肿瘤学 | 56篇 |
出版年
2024年 | 24篇 |
2023年 | 91篇 |
2022年 | 177篇 |
2021年 | 189篇 |
2020年 | 145篇 |
2019年 | 166篇 |
2018年 | 143篇 |
2017年 | 192篇 |
2016年 | 173篇 |
2015年 | 179篇 |
2014年 | 259篇 |
2013年 | 345篇 |
2012年 | 307篇 |
2011年 | 320篇 |
2010年 | 236篇 |
2009年 | 185篇 |
2008年 | 229篇 |
2007年 | 209篇 |
2006年 | 189篇 |
2005年 | 169篇 |
2004年 | 125篇 |
2003年 | 127篇 |
2002年 | 95篇 |
2001年 | 105篇 |
2000年 | 72篇 |
1999年 | 63篇 |
1998年 | 67篇 |
1997年 | 67篇 |
1996年 | 49篇 |
1995年 | 58篇 |
1994年 | 63篇 |
1993年 | 54篇 |
1992年 | 54篇 |
1991年 | 26篇 |
1990年 | 42篇 |
1989年 | 38篇 |
1988年 | 36篇 |
1987年 | 29篇 |
1986年 | 28篇 |
1985年 | 25篇 |
1984年 | 37篇 |
1983年 | 22篇 |
1982年 | 30篇 |
1981年 | 15篇 |
1980年 | 23篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 7篇 |
1973年 | 5篇 |
排序方式: 共有5334条查询结果,搜索用时 453 毫秒
1.
2.
骨碎补是历代临床常用中药,具有疗伤止痛、补肾强骨、消风祛斑等功效。其主要含黄酮、苯丙素、三萜、酚酸及其苷等类化学成分,现代研究表明骨碎补具有抗骨质疏松、促进骨折愈合、促软骨再生、护牙健齿、保护肾功能、抗炎、防治中毒性耳聋、降血脂等多种生物活性,开发前景广阔。本文对近年来骨碎补的化学成分、药理作用及临床应用研究进行综述,以期为骨碎补的进一步深入系统的研究和开发利用提供依据。 相似文献
3.
《Vaccine》2021,39(30):4099-4107
The fungal genus Candida includes common commensals of the human mucosal membranes, and the most prevalently isolated species, C. albicans, poses a threat of candidemia and disseminated infection associated with an unacceptably high mortality rate and an immense $4 billion burden (US) yearly. Nevertheless, the demand for a vaccine remains wholly unfulfilled and increasingly pressing. We developed a double-peptide construct that is feasible for use in humans with the intention of preventing morbid infection by targeting epitopes derived from fructose bisphosphate aldolase (Fba) and methionine synthase (Met6) which are expressed on the C. albicans cell surface. To test the applicability of the design, we vaccinated mice via the intramuscular (IM) route with the conjugate denoted Fba-Met6 MP12 and showed that the vaccine enhanced survival against a lethal challenge. Because overall endpoint IgG1 and IgG2a antibody titers were robust and these mouse subclasses are associated with protective functionality, we investigated the potential of Fba and Met6 specific antibodies to facilitate the well-defined anti-Candida response by complement, which opsonizes fungi for degradation by primary effectors. Notably, reductions in the fungal burdens and enhanced survival were both abrogated in MP12-vaccinated mice that were pre-challenge dosed with cobra venom factor (CVF), a complement depleting factor. Altogether, we demonstrated that complement is relevant to MP12-based protection against disseminated C. albicans, delineating that a novel, multivalent targeted vaccine against proteins on the surface of C. albicans can enhance the natural response to infection. 相似文献
4.
5.
提出了文题的计算模型,它采用非线性弹塑性蠕变有限元法,计算构件危险点在高温及周期保载的交变载荷谱作用下的应力应变响应,以应变范围区分法累积损伤,从而求出构件的疲劳寿命,并以带孔矩形薄板为例作了计算与验证,结果吻合较好,可供工程应用。 相似文献
6.
静脉预注H1,H2受体阻滞药对减轻鱼精蛋白副作用的研究 总被引:3,自引:0,他引:3
将30例ASD、VSD患者随机分为对照与预防用药两组,对比观察H1、H2受体阻滞药苯海拉明、西米替丁对减轻鱼精蛋白副作用的效果和应用鱼精蛋白后补体C3、C4、CH50浓度变化。结果发现预防用药组血液动力学变化明显小于对照组,两组之间差异显著(P<0.01)。应用鱼精蛋白后C3、C4、CH50均下降,与用药前相比差异显著(P<0.01)。提示鱼精蛋白中和肝素可引起补体激活、组胺释放,H1、H2受体阻滞药能够减轻鱼精蛋白引起的血压下降。 相似文献
7.
Dario Roccatello Marco Formica Guido Cavalli Maria C. Amprimo Maria G. Pignatelli Paolo Costa Ruggero de Paulis Giacomo Quattrocchio rea Molino Gianbeppe Giordano 《Artificial organs》1990,14(1):69-72
Neutrophil oxidative metabolism, C3d and beta 2 microglobulin levels, were assessed in nine consecutive patients undergoing cardiopulmonary bypass surgery with polypropylene hollow fiber oxygenators for open cardiac operations. Generation of oxygen free radicals by neutrophils was measured as luminol-enhanced chemiluminescence after stimulation with opsonized Zymosan and phorbol myristate acetate. A significant increase in light emission was detected by using both of the chemiluminescence stimulators. Moreover, a remarkable and significant increase in C3d levels was found already at 10 min. Conversely minimal changes in levels of beta 2 microglobulin were detected during cardiopulmonary bypass surgery. These data suggest that the impact of the patient blood with the foreign surface of cardiopulmonary bypass results in activation of phagocyte cells with increased potential in oxygen consumption. These effects could be partially complement-mediated. 相似文献
8.
Neutrophil Oxygen Radical Production by Dialysis Membranes 总被引:1,自引:0,他引:1
The ability of different dialysis membranes to activate polymorphonuclearneutrophil oxygen radical production was investigated with chemiluminescence.All the six membranes, namely cuprophan, cellulose acetate,polycarbonate, polysulphone, polyacrilonitrile and polymethylmethacrylatewere able to interact with neutrophils and stimulate their oxygenradical production, the highest responses being seen with polyacrilonitrile,polymethylmethacrylate and polycarbonate. To analyse the roleof complement in this interaction, fresh plasma, heat inactivatedand zymosan-activated plasma were added: with fresh plasma oxygenradical production was stimulated on cuprophan, cellulose acetateand polysulphone, not modified on polycarbonate, and decreasedon polyacrilonitrile and polymethylmethacrylate. With heat-inactivatedplasma, the responses were decreased or abrogated on all themembranes except polycarbonate and polymethylmethacrylate, whereaswith zymosanactivated plasma similar responses to fresh plasmawere observed. In addition, when plasma was used to precoatthe membrane, cuprophan, cellulose acetate and polysulphonedisclosed an enhanced neutrophil oxidative burst, while precoatedpolyacrilonitrile and polymethylmethacrylate were less stimulatorythan uncoated membranes. In contrast the precoating of polycarbonatedid not modify oxygen radical production. These data suggestthat neutrophil activation occurs by direct membrane neutrophilinteraction. Plasmatic factors modulate this interaction butcomplement seems involved on cellulosic and polysulphone membranesonly. Therefore, it appears that oxygen radicals produced fromcontact of neutrophils with the dialysis membrane might playan initial and/or additional role in the events occurring atthe initiation of haemodialysis. 相似文献
9.
Stanley A. Klein 《Brain topography》1993,6(1):79-82
Summary There are some occasions when it is better to use the Laplacian of the scalp voltages (e.g., for topographic displays and dipole source localization) and other occasions when it is better to use the original voltages (e.g., for comparison to non-Laplacian topography maps). This paper presents a simple algorithm for going between these two representations of the data. The inverse Laplacian involves iterative feedback. An Excel spreadsheet implementation of the algorithm is presented.This research was supported by grant AFOSR 89-0238 from the Air Force Office of Sponsored Research. 相似文献
10.
Systolic and diastolic blood pressures were measured on 254 monozygotic (MZ) and 260 dizygotic (DZ) male twin pairs, during middle age (average age 48 years) and at two later age points. Genetic and environmental components of covariation were modeled by time series. For both measures, shared environmental influences were absent and specific environmental influences were largely time-specific. Although heritability was about 0.5 at each time point, genetic variation present at middle age contributed only about 60% to that present 9 years later, the remaining 40% being new. Fifteen years later, at the third time point, no new genetic variation was evident, variation in individual differences being entirely attributable to genetic differences laid down at the two earlier ages. © 1993 Wiley-Liss, Inc. 相似文献