全文获取类型
收费全文 | 12129篇 |
免费 | 663篇 |
国内免费 | 460篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 269篇 |
妇产科学 | 79篇 |
基础医学 | 1504篇 |
口腔科学 | 139篇 |
临床医学 | 1126篇 |
内科学 | 2455篇 |
皮肤病学 | 140篇 |
神经病学 | 593篇 |
特种医学 | 195篇 |
外科学 | 651篇 |
综合类 | 1815篇 |
预防医学 | 663篇 |
眼科学 | 83篇 |
药学 | 2556篇 |
5篇 | |
中国医学 | 624篇 |
肿瘤学 | 315篇 |
出版年
2024年 | 13篇 |
2023年 | 81篇 |
2022年 | 223篇 |
2021年 | 325篇 |
2020年 | 332篇 |
2019年 | 220篇 |
2018年 | 291篇 |
2017年 | 263篇 |
2016年 | 335篇 |
2015年 | 284篇 |
2014年 | 580篇 |
2013年 | 873篇 |
2012年 | 591篇 |
2011年 | 699篇 |
2010年 | 552篇 |
2009年 | 512篇 |
2008年 | 584篇 |
2007年 | 573篇 |
2006年 | 546篇 |
2005年 | 524篇 |
2004年 | 474篇 |
2003年 | 437篇 |
2002年 | 390篇 |
2001年 | 328篇 |
2000年 | 321篇 |
1999年 | 287篇 |
1998年 | 231篇 |
1997年 | 237篇 |
1996年 | 225篇 |
1995年 | 192篇 |
1994年 | 176篇 |
1993年 | 152篇 |
1992年 | 152篇 |
1991年 | 128篇 |
1990年 | 126篇 |
1989年 | 112篇 |
1988年 | 107篇 |
1987年 | 90篇 |
1986年 | 84篇 |
1985年 | 105篇 |
1984年 | 114篇 |
1983年 | 65篇 |
1982年 | 70篇 |
1981年 | 52篇 |
1980年 | 51篇 |
1979年 | 26篇 |
1978年 | 31篇 |
1977年 | 26篇 |
1976年 | 17篇 |
1974年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The non-sulfhydryl selective angiotensin-converting enzyme inhibitor benazepril (20 mg daily) was compared with hydrochlorothiazide (50 mg daily) in post-infarction (6-24 months) patients with symptomatic (NYHA functional class 2) mild heart failure. No concomitant drug therapy was given. The study had a double-blind cross-over design with 3-month treatment periods. Both drugs were well tolerated, and both caused a similar reduction in systolic blood pressure. Heart rate was higher with the diuretic. Benazepril improved the NYHA functional class in 17 out of 29 (59%) patients, whereas one patient improved with hydrochlorothiazide (P = 0.0004). With regard to global efficacy score, benazepril was also superior. Thus, angiotensin-converting enzyme inhibitors may be superior to diuretics as first-choice therapy in symptomatic mild heart failure. 相似文献
32.
33.
ANGIOTENSIN CONVERTING ENZYME (ACE) INHIBITORS AND KININ METABOLISM: EVIDENCE THAT ACE INHIBITORS MAY INHIBIT A KININASE OTHER THAN ACE 总被引:1,自引:0,他引:1
Duncan J. Campbell 《Clinical and experimental pharmacology & physiology》1995,22(12):903-911
1. Angiotensin converting enzyme (ACE) converts angiotensin I to angiotensin II, and also metabolizes bradykinin-(1–9) to bradykinin-(1–7) and bradykinin-(1–7) to bradykinin-(1–5). Increases in endogenous kinin levels may contribute to the therapeutic effects of ACE inhibitors. 2. ACE inhibitors increase vascular levels of both bradykinin-(1–9) and its ACE cleavage product bradykinin-(1–7), at doses below the threshold for ACE inhibition, leading to the proposal that ACE inhibitors may also inhibit a non-ACE kininase which cleaves both kinin peptides; this non-ACE kininase may be the major pathway of kinin metabolism in the vasculature and some other tissues. 3. In support of this proposal, ACE inhibitors potentiate bradykinin-(1–9) effects at doses which have little or no effect on ACE activity, as indicated by angiotensin I conversion to angiotensin II. ACE inhibitors also potentiate the actions of ACE-resistant kinin analogues, which may be susceptible to metabolism by a non-ACE kininase. 4. Identification and characterization of the putative non-ACE kininase which is inhibited by ACE inhibitors may reveal novel approaches to the tissue-specific modulation of kinin levels. 相似文献
34.
Margaret A. O’Leary Brian Prakash Krishnan Amy McKendry Geoffrey K. Isbister 《Toxicon》2007,50(2):206-213
Recently it has been suggested that the Australian snake antivenoms made by CSL Ltd. are in fact not truly monovalent and may contain antibodies to other snake venoms because the horses are injected with multiple snake venoms. It is unclear to what extent various monovalent antivenoms can neutralise the effect of other venoms, whether this is due to a mixture of antibodies or true cross-reactivity, and whether this has any clinical significance. We aimed to study the immunological and functional properties of brown snake (Pseudonaja spp.) antivenom (BSAV) and tiger snake (Notechis spp.) antivenom (TSAV) against their respective venoms using enzyme immunoassays (EIA) and in vitro clotting studies. There was significant overlap between the two antivenoms with both TSAV and BSAV being detected by EIA on brown snake venom (BSV)-coated and tiger snake venom (TSV)-coated wells, respectively. In a competition EIA, increasing amounts of immunoaffinity-purified hen anti-brown antibodies (IgYp) mixed with TSAV reduced TSAV measured on TSV-coated wells. Both BSAV and TSAV prevented the clotting activity of both venoms. IgYp also prevented the clotting activity of TSV, suggesting true cross-reactivity. The cross-reactivity of TSAV and BSAV with BSV and TSV, respectively, was likely due to each being a mixture of anti-brown and anti-tiger antibodies, but there was partial cross-reactivity demonstrated by the effect of IgYp. Single-polyvalent antivenom for brown snake and tiger snake may be feasible in the future. 相似文献
35.
36.
单甲氧聚乙二醇化学修饰药物酶的研究进展 总被引:4,自引:0,他引:4
用单甲氧基聚乙二醉(1)化学修饰药物酶是生化药物研究开发的重要手段之一。本文综述了1化学修饰药物酶的一般方法及修饰后酶在生物和理化性质方面的变化,同时对1研究前景进行展望,并指出了尚待解决的问题。 相似文献
37.
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
38.
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
39.
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
40.
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