全文获取类型
收费全文 | 1933篇 |
免费 | 131篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 112篇 |
妇产科学 | 29篇 |
基础医学 | 208篇 |
口腔科学 | 52篇 |
临床医学 | 198篇 |
内科学 | 460篇 |
皮肤病学 | 72篇 |
神经病学 | 100篇 |
特种医学 | 360篇 |
外科学 | 152篇 |
综合类 | 19篇 |
一般理论 | 1篇 |
预防医学 | 77篇 |
眼科学 | 34篇 |
药学 | 69篇 |
肿瘤学 | 129篇 |
出版年
2023年 | 7篇 |
2021年 | 27篇 |
2020年 | 15篇 |
2019年 | 23篇 |
2018年 | 41篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 38篇 |
2014年 | 42篇 |
2013年 | 59篇 |
2012年 | 58篇 |
2011年 | 77篇 |
2010年 | 59篇 |
2009年 | 55篇 |
2008年 | 46篇 |
2007年 | 70篇 |
2006年 | 56篇 |
2005年 | 62篇 |
2004年 | 40篇 |
2003年 | 32篇 |
2002年 | 41篇 |
2001年 | 31篇 |
2000年 | 37篇 |
1999年 | 40篇 |
1998年 | 106篇 |
1997年 | 72篇 |
1996年 | 83篇 |
1995年 | 64篇 |
1994年 | 61篇 |
1993年 | 67篇 |
1992年 | 26篇 |
1991年 | 34篇 |
1990年 | 40篇 |
1989年 | 65篇 |
1988年 | 47篇 |
1987年 | 60篇 |
1986年 | 39篇 |
1985年 | 51篇 |
1984年 | 34篇 |
1983年 | 19篇 |
1982年 | 23篇 |
1981年 | 24篇 |
1980年 | 31篇 |
1979年 | 9篇 |
1978年 | 19篇 |
1977年 | 25篇 |
1976年 | 22篇 |
1975年 | 18篇 |
1973年 | 5篇 |
1972年 | 6篇 |
排序方式: 共有2077条查询结果,搜索用时 31 毫秒
21.
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
22.
Plasma R binder deficiency and neurologic disease 总被引:1,自引:0,他引:1
23.
Mutation spectrum and genotype-phenotype analyses in Cowden disease and Bannayan-Zonana syndrome, two hamartoma syndromes with germline PTEN mutation 总被引:22,自引:1,他引:22
Marsh DJ; Coulon V; Lunetta KL; Rocca-Serra P; Dahia PL; Zheng Z; Liaw D; Caron S; Duboue B; Lin AY; Richardson AL; Bonnetblanc JM; Bressieux JM; Cabarrot-Moreau A; Chompret A; Demange L; Eeles RA; Yahanda AM; Fearon ER; Fricker JP; Gorlin RJ; Hodgson SV; Huson S; Lacombe D; Eng C 《Human molecular genetics》1998,7(3):507-515
The tumour suppressor gene PTEN , which maps to 10q23.3 and encodes a 403
amino acid dual specificity phosphatase (protein tyrosine phosphatase;
PTPase), was shown recently to play a broad role in human malignancy.
Somatic PTEN deletions and mutations were observed in sporadic breast,
brain, prostate and kidney cancer cell lines and in several primary tumours
such as endometrial carcinomas, malignant melanoma and thyroid tumours. In
addition, PTEN was identified as the susceptibility gene for two hamartoma
syndromes: Cowden disease (CD; MIM 158350) and Bannayan-Zonana (BZS) or
Ruvalcaba-Riley-Smith syndrome (MIM 153480). Constitutive DNA from 37 CD
families and seven BZS families was screened for germline PTEN mutations.
PTEN mutations were identified in 30 of 37 (81%) CD families, including
missense and nonsense point mutations, deletions, insertions, a
deletion/insertion and splice site mutations. These mutations were
scattered over the entire length of PTEN , with the exception of the first,
fourth and last exons. A 'hot spot' for PTEN mutation in CD was identified
in exon 5 that contains the PTPase core motif, with 13 of 30 (43%) CD
mutations identified in this exon. Seven of 30 (23%) were within the core
motif, the majority (five of seven) of which were missense mutations,
possibly pointing to the functional significance of this region. Germline
PTEN mutations were identified in four of seven (57%) BZS families studied.
Interestingly, none of these mutations was observed in the PTPase core
motif. It is also worthy of note that a single nonsense point mutation,
R233X, was observed in the germline DNA from two unrelated CD families and
one BZS family. Genotype-phenotype studies were not performed on this small
group of BZS families. However, genotype-phenotype analysis inthe group of
CD families revealed two possible associations worthy of follow-up in
independent analyses. The first was an association noted in the group of CD
families with breast disease. A correlation was observed between the
presence/absence of a PTEN mutation and the type of breast involvement
(unaffected versus benign versus malignant). Specifically and more
directly, an association was also observed between the presence of a PTEN
mutation and malignant breast disease. Secondly, there appeared to be an
interdependent association between mutations upstream and within the PTPase
core motif, the core motif containing the majority of missense mutations,
and the involvement of all major organ systems (central nervous system,
thyroid, breast, skin and gastrointestinal tract). However, these
observations would need to be confirmed by studying a larger number of CD
families.
相似文献
24.
25.
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
26.
27.
Evolutionary silencing of the human elastase I gene (ELA1) 总被引:6,自引:0,他引:6
28.
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
29.
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
30.
An unusual benign multicentric esophageal granular cell tumor (granular cell myoblastoma) associated with 16 other similar tumors in the skin, vulva, breast, and tongue of 1 patient is described. There was a family history of granular cell tumors in the patient's mother; this has not been previously described. The pathologic findings and controversial histogenesis of granular cell tumors are discussed in an effort to delete the erroneous term "myoblastoma" from the radiologist's vocabulary. Granular cell tumors of the esophagus are also specifically reviewed. 相似文献