全文获取类型
收费全文 | 1504篇 |
免费 | 163篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 98篇 |
妇产科学 | 17篇 |
基础医学 | 142篇 |
口腔科学 | 29篇 |
临床医学 | 156篇 |
内科学 | 266篇 |
皮肤病学 | 19篇 |
神经病学 | 66篇 |
特种医学 | 308篇 |
外科学 | 148篇 |
综合类 | 18篇 |
预防医学 | 213篇 |
眼科学 | 9篇 |
药学 | 42篇 |
肿瘤学 | 91篇 |
出版年
2021年 | 15篇 |
2020年 | 10篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2016年 | 13篇 |
2015年 | 29篇 |
2014年 | 27篇 |
2013年 | 28篇 |
2012年 | 25篇 |
2011年 | 43篇 |
2010年 | 59篇 |
2009年 | 38篇 |
2008年 | 32篇 |
2007年 | 52篇 |
2006年 | 40篇 |
2005年 | 36篇 |
2004年 | 53篇 |
2003年 | 39篇 |
2002年 | 44篇 |
2001年 | 23篇 |
2000年 | 24篇 |
1999年 | 35篇 |
1998年 | 100篇 |
1997年 | 80篇 |
1996年 | 87篇 |
1995年 | 55篇 |
1994年 | 57篇 |
1993年 | 63篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 20篇 |
1989年 | 43篇 |
1988年 | 34篇 |
1987年 | 50篇 |
1986年 | 31篇 |
1985年 | 36篇 |
1984年 | 34篇 |
1983年 | 24篇 |
1982年 | 23篇 |
1981年 | 25篇 |
1980年 | 30篇 |
1979年 | 16篇 |
1978年 | 26篇 |
1977年 | 27篇 |
1976年 | 30篇 |
1975年 | 18篇 |
1970年 | 3篇 |
1930年 | 5篇 |
1929年 | 5篇 |
1928年 | 3篇 |
排序方式: 共有1680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.
Evolutionary silencing of the human elastase I gene (ELA1) 总被引:6,自引:0,他引:6
15.
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
16.
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
17.
Understanding AIDS: historical interpretations and the limits of biomedical individualism. 总被引:8,自引:5,他引:3 下载免费PDF全文
The popular and scientific understanding of acquired immunodeficiency syndrome (AIDS) in the United States has been shaped by successive historical constructions or paradigms of disease. In the first paradigm, AIDS was conceived of as a "gay plague," by analogy with the sudden, devastating epidemics of the past. In the second, AIDS was normalized as a chronic disease to be managed medically over the long term. By examining and extending critiques of both paradigms, it is possible to discern the emergence of an alternative paradigm of AIDS as a collective chronic infectious disease and persistent pandemic. Each of these constructions of AIDS incorporates distinct views of the etiology, prevention, pathology, and treatment of disease; each tacitly promotes different conceptions of the proper allocation of individual and social responsibility for AIDS. This paper focuses on individualistic vs collective, and biomedical vs social and historical, understandings of disease. It analyzes the use of individualism as methodology and as ideology, criticizes some basic assumptions of the biomedical model, and discusses alternative strategies for scientific research, health policy, and disease prevention. 相似文献
18.
Fee EJ 《Clinical linguistics & phonetics》1995,9(3):189-209
This paper provides a characterization of the phonological system of a family of specifically language-impaired (SLI) individuals. Morphological and syntactic data from these same subjects have previously been presented in Gopnik and Crago (1991) and Guilfoyle (1991). Data were collected from eight subjects, all family members, ranging from 7 to 46 years of age. Language samples were obtained at two sessions, 17 months apart, and analysed according to a revised version of the phonological assessment procedures outlined in Ingram (1981, 1989). Results indicated that these SLI subjects acquired the phonological inventory of English following the normal developmental sequence, but at an extremely delayed rate. In contrast, these subjects never achieved adult competency in reproducing the complex syllable patterns of English, as evidenced by the fact that consonants in syllable-final position and clusters were particularly susceptible to deletion or substitution errors. It is argued that these data are consistent with a linguistically based account of this impairment, which is manifested in the phonological component by the inability to construct learned, language-specific rules. 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
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