全文获取类型
收费全文 | 1329篇 |
免费 | 91篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 91篇 |
妇产科学 | 12篇 |
基础医学 | 111篇 |
口腔科学 | 25篇 |
临床医学 | 150篇 |
内科学 | 280篇 |
皮肤病学 | 19篇 |
神经病学 | 45篇 |
特种医学 | 310篇 |
外科学 | 141篇 |
综合类 | 10篇 |
预防医学 | 32篇 |
眼科学 | 13篇 |
药学 | 122篇 |
肿瘤学 | 68篇 |
出版年
2023年 | 2篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 30篇 |
2012年 | 31篇 |
2011年 | 24篇 |
2010年 | 42篇 |
2009年 | 28篇 |
2008年 | 24篇 |
2007年 | 42篇 |
2006年 | 39篇 |
2005年 | 35篇 |
2004年 | 44篇 |
2003年 | 23篇 |
2002年 | 30篇 |
2001年 | 29篇 |
2000年 | 17篇 |
1999年 | 29篇 |
1998年 | 98篇 |
1997年 | 73篇 |
1996年 | 79篇 |
1995年 | 54篇 |
1994年 | 56篇 |
1993年 | 64篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 16篇 |
1989年 | 48篇 |
1988年 | 30篇 |
1987年 | 41篇 |
1986年 | 27篇 |
1985年 | 36篇 |
1984年 | 24篇 |
1983年 | 18篇 |
1982年 | 24篇 |
1981年 | 23篇 |
1980年 | 31篇 |
1979年 | 8篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1975年 | 14篇 |
1930年 | 1篇 |
排序方式: 共有1432条查询结果,搜索用时 0 毫秒
11.
Role of nitric oxide in the biology, physiology and pathophysiology of reproduction 总被引:13,自引:0,他引:13
Following its benchmark discovery, nitric oxide (NO) is nowknown to play important functional roles in a variety of physiologicalsystems. Within the vasculature, NO induces vasodilation, inhibitsplatelet aggregation, prevents neutrophil/platelet adhesionto endothelial cells, inhibits smooth muscle cell proliferationand migration, regulates programmed cell death (apoptosis) andmaintains endothelial cell barrier function. NO generated byneurons acts as a neurotransmitter, whereas NO generated bymacrophages in response to invading microbes acts as an antimicrobialagent. Because neurons, blood vessels and cells of the immunesystem are integral parts of the reproductive organs, and inview of the important functional role that NO plays in thosesystems, it is likely that NO is an important regulator of thebiology and physiology of the reproductive system. Indeed, inthe past 10 years, NO has established itself as a polyvalentmolecule which plays a decisive role in regulating multiplefunctions within the female as well as the male reproductivesystem. This review provides an overview of the role of NO invarious reproductive organs under physiological and pathologicalconditions. 相似文献
12.
ATRX encodes a novel member of the SNF2 family of proteins: mutations point to a common mechanism underlying the ATR-X syndrome 总被引:11,自引:3,他引:11
Picketts DJ; Higgs DR; Bachoo S; Blake DJ; Quarrell OW; Gibbons RJ 《Human molecular genetics》1996,5(12):1899-1907
It was shown recently that mutations of the ATRX gene give rise to a
severe, X-linked form of syndromal mental retardation associated with alpha
thalassaemia (ATR-X syndrome). In this study, we have characterised the
full-length cDNA and predicted structure of the ATRX protein. Comparative
analysis shows that it is an entirely new member of the SNF2 subgroup of a
superfamily of proteins with similar ATPase and helicase domains. ATRX
probably acts as a regulator of gene expression. Definition of its genomic
structure enabled us to identify four novel splicing defects by screening
52 affected individuals. Correlation between these and previously
identified mutations with variations in the ATR-X phenotype provides
insights into the pathophysiology of this disease and the normal role of
the ATRX protein in vivo.
相似文献
13.
14.
15.
Evolutionary silencing of the human elastase I gene (ELA1) 总被引:6,自引:0,他引:6
16.
Huisman JA; Paulussen RJ; Geurts TB; Odink J; Rekers H 《Human reproduction (Oxford, England)》1997,12(1):34-38
The objective was to demonstrate bioequivalence between s.c. and i.m.
administration of Humegon (FSH/LH ratio 1:1) and Normegon (FSH/LH ratio
3:1). In two randomized, single-centre, cross-over studies, 18 healthy
volunteers on each formulation were assigned to one of the two
administration sequences. Subjects were given single doses of one of the
above gonadotrophins after endogenous gonadotrophin production had first
been suppressed using high-dose oral contraceptive. Subsequently, rate
(Cmax, tmax) and extent (AUC) of absorption of follicle stimulating hormone
(FSH) and luteinizing hormone (LH) were determined for 14 days. For Cmax
and AUC, analysis of variance (ANOVA) was performed on log-transformed data
and for tmax ANOVA was performed on ranks. Intramuscular and s.c.
injections of Humegon were bioequivalent with respect to the main
pharmacokinetic parameters, being AUC and Cmax of FSH absorption.
Intramuscular and s.c. injections of Normegon were bioequivalent with
respect to the AUC of FSH and not bioequivalent with respect to the Cmax of
FSH. For tmax of FSH as well as for most LH variables of both preparations,
bioequivalence could not be proven due to the high intra- and
interindividual variability and/or concentrations being close to the
detection limit. Thus, the main pharmacokinetic FSH variables after i.m.
and s.c. administration of Humegon and Normegon were bioequivalent.
相似文献
17.
Lesions of the articular surfaces of the knee have been managed by various techniques over the last 50 years. Surgical management has involved: excising the damaged area, refashioning the underlying bone to produce a fibrous response, and introducing allograft, autograft and synthetic materials to encourage a repair matrix. The techniques and their pitfalls are reviewed and discussed, and suggestions made as to the direction of future studies for the repair of osteochondral lesions in the painful knee. 相似文献
18.
Eva Delpón Juan Tamargo José Sánchez-Chapula 《Naunyn-Schmiedeberg's archives of pharmacology》1991,344(6):645-652
Summary The effects of imipramine, a tricyclic antidepressant, on action potential characteristics and plateau membrane currents were studied in isolated guineapig ventricular myocytes, using the whole cell configuration of the patch-clamp technique. Imipramine (1, 5 and 15 mol/l) decreased in a concentration-dependent manner the amplitude and shortened the duration of the action potential, but it had no effect on resting membrane potential. At all three concentrations tested, imipramine decreased the delayed outward potassium current, this effect being apparently voltage-independent since it did not modify the activation curve. Imipramine, 5 and 15 mol/l, also produced an inhibition of the peak high threshold calcium current, but did not change the shape of the current-voltage relationship or the apparent reversal potential of this current. Therefore, imipramine probably decreased the maximum available calcium conductance. However, the inward rectifying potassium current was not affected by any concentration of imipramine tested. Imipramine, 1 and 5 mol/l, shortened the duration of the action potentials elicited in the presence of the inorganic calcium channel blocker cobalt chloride, and at 5, but not at 1 mol/l, also shortened the action potentials obtained in the presence of the sodium channel blocker tetrodotoxin. Washout of imipramine completely reversed all its effects within 15 minutes. All these results suggest that imipramine at a concentration of 1 mol/l produced a shortening in action potential duration by inhibiting the late sodium current flowing during the plateau phase of the action potential. At concentrations of 5 and 15 mol/l the effect of imipramine on action potential duration can also be explained by a blocking effect on the high threshold calcium current.
Send offprint requests to E. Delpón at the above address 相似文献
19.
Frequency of the ATM IVS10-6T→G variant in Australian multiple-case breast cancer families
下载免费PDF全文
![点击此处可从《Breast cancer research : BCR》网站下载免费的PDF全文](/ch/ext_images/free.gif)
20.
Hypospadias trends in two US surveillance systems 总被引:6,自引:0,他引:6
OBJECTIVE: Hypospadias is a common congenital anomaly, the cause of which is unknown. Unexplained increases in the rates of hypospadias occurred in five European countries in the 1970s and 1980s. We examined data from two birth defects surveillance systems in the United States for evidence of similar trends. METHODOLOGY: The Metropolitan Atlanta Congenital Defects Program (MACDP) provided birth prevalence rates from 1968 to 1993. The nationwide Birth Defects Monitoring Program (BDMP) provided rates from 1970 to 1993. MACDP data are population-based and could be categorized by the severity of the hypospadias. BDMP data allowed analysis of rate trends for the four census regions of the United States. RESULTS: Data from both surveillance systems showed an approximate doubling of hypospadias rates in the 1970s and 1980s. MACDP data showed that the rate of severe cases increased while the ratio of mild to severe cases decreased. BDMP data showed that hypospadias rates increased markedly in all four regions of the United States. CONCLUSIONS: The observed increases are unlikely to be attributable to increased sensitivity of the surveillance systems or the identification of more mild cases by physicians over time, because either trend would have increased rather than decreased the ratio of mild to severe cases. If real, these trends represent the largest number of cases and the first report of an increase in hypospadias rates outside of Europe. Additional investigation of a possible increase in hypospadias rates is warranted. 相似文献