全文获取类型
收费全文 | 18636篇 |
免费 | 1312篇 |
国内免费 | 724篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 291篇 |
妇产科学 | 83篇 |
基础医学 | 2102篇 |
口腔科学 | 745篇 |
临床医学 | 1730篇 |
内科学 | 2992篇 |
皮肤病学 | 158篇 |
神经病学 | 792篇 |
特种医学 | 473篇 |
外国民族医学 | 1篇 |
外科学 | 1100篇 |
综合类 | 2411篇 |
现状与发展 | 1篇 |
预防医学 | 906篇 |
眼科学 | 228篇 |
药学 | 5105篇 |
5篇 | |
中国医学 | 1118篇 |
肿瘤学 | 392篇 |
出版年
2024年 | 35篇 |
2023年 | 172篇 |
2022年 | 499篇 |
2021年 | 681篇 |
2020年 | 572篇 |
2019年 | 491篇 |
2018年 | 555篇 |
2017年 | 527篇 |
2016年 | 598篇 |
2015年 | 548篇 |
2014年 | 958篇 |
2013年 | 1414篇 |
2012年 | 899篇 |
2011年 | 1083篇 |
2010年 | 839篇 |
2009年 | 785篇 |
2008年 | 836篇 |
2007年 | 834篇 |
2006年 | 789篇 |
2005年 | 723篇 |
2004年 | 680篇 |
2003年 | 632篇 |
2002年 | 537篇 |
2001年 | 484篇 |
2000年 | 456篇 |
1999年 | 419篇 |
1998年 | 351篇 |
1997年 | 350篇 |
1996年 | 319篇 |
1995年 | 279篇 |
1994年 | 244篇 |
1993年 | 225篇 |
1992年 | 239篇 |
1991年 | 188篇 |
1990年 | 179篇 |
1989年 | 150篇 |
1988年 | 158篇 |
1987年 | 112篇 |
1986年 | 111篇 |
1985年 | 146篇 |
1984年 | 128篇 |
1983年 | 80篇 |
1982年 | 80篇 |
1981年 | 62篇 |
1980年 | 59篇 |
1979年 | 29篇 |
1978年 | 36篇 |
1977年 | 29篇 |
1976年 | 21篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
基于Lyapnuov泛函方法,研究了满足匹配条件的不确定性时滞系统的鲁棒稳定性及具有稳定度β〉0鲁棒稳定性,给出了已有结果不能推出的新判据。这些新判据对已有结果难以使用的情况下也可有是有效的,或有时减少了已有结果的保守性。 相似文献
102.
J. Hilton R.J. Dearman N. Sattar D.A. Basketter I. Kimber 《Food and chemical toxicology》1997,35(12):1209-1218
Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses. 相似文献
103.
蛇毒治疗不能解释肺动脉高压的研究 总被引:1,自引:1,他引:0
本通过对不能解释的肺动脉高压患,进行右心导管测定肺动脉平均压(PAMP)作为主要对照指标,观察蛇毒制品(精制溶栓酶)的急性药物试验和近期药物试验。发现该药物在近期有理想的降低PAMP作用,症状及胸片、超声心动图异常也明显取得改善,提示其可能为治疗该病的理想药物。 相似文献
104.
105.
Saturated solubility and reaction rate constants for the decomposition of benzoyl peroxide in solution and suspension were determined for use in formulation development. The solvents studied included ethanol, propylene glycol, and cosolvent mixtures of PEG 400 and water. The solubility of benzoyl peroxide was inversely related to the solvent polarity, with greater solubility occurring with semipolar solvents. The stability of benzoyl peroxide in solution was dependent on the solvent, concentration of benzoyl peroxide, and temperature. The compound was least stable in PEG 400. Stability was improved when water was added to PEG 400. Similar solvent effects were observed in suspension. In benzoyl peroxide suspensions of PEG 400 and PEG 400/water blends, benzoyl peroxide stability was dependent on solubility, with improved stability occurring in blends where the benzoyl peroxide was least soluble. Thus, solution formulations of benzoyl peroxide in pharmaceutically acceptable solvents are unlikely to show good stability; however, suspension formulations should be reasonably stable if the vehicle is selected to provide low benzoyl peroxide solubility. 相似文献
106.
氧氟沙星滴耳剂的高效液相色谱分析和稳定性研究 总被引:6,自引:2,他引:4
本文采用反相高效液相色谱法考察了氧氟沙星滴耳剂的稳定性。该法简便、迅速、专属性强、精密度好,制剂回收率为99.97%。经光照、高温、低温和加速试验,结果表明:本制剂对冷和热稳定,对光不稳定。建议氧氟沙星滴耳剂暂定有效期2年,使用中应注意避光保存。 相似文献
107.
重症胰腺炎动物模型制作及发病机理的研究 总被引:6,自引:1,他引:5
为探讨胰腺炎的发病机理,作者采用大鼠(n=58只)十二指肠结扎法和犬(n=46条)胰管内注射自身胆汁法制作重症胰腺炎的动物模型。该模型接近人类急性胰腺炎的发病因素,方法可靠,操作简便,费用便宜。前者适用于小动物实验,后者宜于大动物实验。作者认为胰管内压力增高和微生物是急性胰腺炎的重要条件;胰酶激活始动时间早在胰管内胆汁和肠液的反流后,胰酶激活的主要部位在腺泡细胞。 相似文献
108.
通过20例有左室肥厚和23例无左室肥厚患者发生急性心肌梗塞时CPK值的比较,发现在梗塞部位相同的情况下,心肌肥厚组的酶值水平高于非心肌肥厚组(13.2±4.8比9.0±4.6U/LP<0.01),这可能与肥厚组酶活力增强和心肌梗塞体积增大有关。 相似文献
109.
Harold P. Schedl Helen D. Wilson Ron L. Horst Karla Christensen Kice Brown 《Nutrition Research》1992,12(12):1541-1547
The circulating concentration of 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] is a physiologic index of enzymatic activity of the renal 1-hydroxylase of 25-hydroxychole-calciferol (25-OH-D3). Hydroxylation of 25-OH-D3 and circulating 1,25-(OH)2D3 are decreased in the streptozotocin diabetic rat. We previously found that activity of another redox enzyme system, cytosolic superoxide dismutase, also decreased in streptozotocin diabetes, can be restored by treatment with glutathione. In the present experiment we tested the effect of glutathione treatment on vitamin D metabolism in control and diabetic rats. Enteral glutathione increased circulating 1,25-(OH)2D3 and decreased 25-OH-D3 in both control and diabetic animals. These results suggest that exogenous glutathione increases 25-OH-D3 1-hydroxylation both under basal conditions in the normal animal and in diabetes-induced depression. 相似文献
110.