全文获取类型
收费全文 | 1414篇 |
免费 | 117篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 100篇 |
妇产科学 | 19篇 |
基础医学 | 223篇 |
口腔科学 | 32篇 |
临床医学 | 196篇 |
内科学 | 287篇 |
皮肤病学 | 23篇 |
神经病学 | 76篇 |
特种医学 | 150篇 |
外科学 | 143篇 |
综合类 | 45篇 |
预防医学 | 60篇 |
眼科学 | 32篇 |
药学 | 88篇 |
肿瘤学 | 63篇 |
出版年
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 12篇 |
2018年 | 33篇 |
2017年 | 14篇 |
2016年 | 28篇 |
2015年 | 34篇 |
2014年 | 43篇 |
2013年 | 64篇 |
2012年 | 53篇 |
2011年 | 55篇 |
2010年 | 67篇 |
2009年 | 57篇 |
2008年 | 52篇 |
2007年 | 49篇 |
2006年 | 46篇 |
2005年 | 48篇 |
2004年 | 30篇 |
2003年 | 37篇 |
2002年 | 20篇 |
2001年 | 22篇 |
2000年 | 23篇 |
1999年 | 19篇 |
1998年 | 42篇 |
1997年 | 46篇 |
1996年 | 50篇 |
1995年 | 38篇 |
1994年 | 29篇 |
1993年 | 36篇 |
1992年 | 33篇 |
1991年 | 20篇 |
1990年 | 35篇 |
1989年 | 29篇 |
1988年 | 25篇 |
1987年 | 34篇 |
1986年 | 29篇 |
1985年 | 32篇 |
1984年 | 13篇 |
1983年 | 19篇 |
1982年 | 9篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 18篇 |
1978年 | 15篇 |
1977年 | 16篇 |
1976年 | 16篇 |
1975年 | 10篇 |
1973年 | 13篇 |
1972年 | 10篇 |
1971年 | 9篇 |
排序方式: 共有1541条查询结果,搜索用时 15 毫秒
1.
Because of its reported ability to induce unscheduled DNA synthesis in the gastric mucosa, the safety of omeprazole, a potentially clinically useful anti-ulcer drug, has been the subject of debate. We have undertaken a detailed computer-based study of structural basis of the putative mutagenicity, genotoxicity and carcinogenicity in rodents of omeprazole and of its sulphenimide, and we conclude that omeprazole is a potential 'genotoxic' carcinogen. The analysis is consistent with the possibility that these activities are associated with the unstable sulphenimide metabolite. 相似文献
2.
3.
Growth factors such as PDGF, VEGF and TGF-β play a pivotal role in the regulation and differentiation of different cell types in the connective tissue, for example fibroblasts and endothelial cells, and in the immune system. Pathophysiologically, these growth factors are thought to play a central role in tumorigenesis, and the use of their inhibitors has led to substantial improvements in tumor therapy. Recent findings also support an important role for growth factors in inflammatory rheumatoid diseases. New developments in the understanding and potential role of these factors in the pathophysiology of rheumatic diseases will be discussed. 相似文献
4.
5.
Silber SJ; Nagy Z; Devroey P; Tournaye H; Van Steirteghem AC 《Human reproduction (Oxford, England)》1997,12(11):2422-2428
The aim of the study was to determine whether a prior diagnostic testicle
biopsy can predict success or failure of testicular sperm extraction (TESE)
with intracytoplasmic sperm injection (ICSI) in patients with
non-obstructive azoospermia caused by testicular failure, and what is the
minimum threshold of sperm production in the testis which must be surpassed
for spermatozoa to reach the ejaculate. Forty- five patients with
non-obstructive azoospermia caused by testicular failure underwent
diagnostic testicle biopsy prior to a planned future TESE-ICSI procedure.
The diagnostic testicle biopsy was analysed quantitatively, and correlated
with the quantitative findings of spermatogenesis in patients with normal
spermatogenesis, as well as with the results of subsequent attempts at
TESE-ICSI. Men with non- obstructive azoospermia caused by germinal failure
had a mean of 0-6 mature spermatids/seminiferous tubule seen on a
diagnostic testicle biopsy, compared to 17-35 mature spermatids/tubule in
men with normal spermatogenesis and obstructive azoospermia. These findings
were the same for all types of testicular failure whether Sertoli cell
only, maturation arrest, cryptorchidism, or post-chemotherapy azoospermia.
Twenty-two of 26 men with mature spermatids found in the prior testis
biopsy had successful retrieval of spermatozoa for ICSI, 12 of their
partners became pregnant, and are either ongoing or delivered. The study
suggests that 4-6 mature spermatids/tubule must be present in the testis
biopsy for any spermatozoa to reach the ejaculate. More than half of
azoospermic patients with germinal failure have minute foci of
spermatogenesis which are insufficient to produce spermatozoa in the
ejaculate. Prior diagnostic testicle biopsy analysed quantitatively (for
the presence of mature spermatids) can predict subsequent success or
failure with TESE-ICSI. Incomplete testicular failure may involve a sparse
multi-focal distribution of spermatogenesis throughout the entire testicle,
rather than a regional distribution. Therefore, it is possible that massive
testicular sampling from many different regions of the testes may not be
necessary for successful TESE-ICSI.
相似文献
6.
β-Lactoglobulin was isolated from infant formulae that were ultra high temperature (UHT) -treated, sterilized or spray-dried. The effect of the isolated β-lactoglobulin on SfaII-fimbriae-mediated adhesion of Escherichia coli to human ileostomy glycoproteins was studied in vitro. β-Lactoglobulin isolated from sterilized formulae was found to perform significantly less well than preparations from spray-dried formulae (p = 0:05). Great heterogeneity was observed in the adhesion inhibitory capacity of β-lactoglobulin isolated from UHT-treated formulae. Therefore, no significant difference was observed between UHT-treated and sterilized formulae or spray-dried formulae (p < 0:10). It can be hypothesized that β-lactoglobulin from spray-dried and some UHT-treated infant formulae may affect the colonization of mucous membranes by E. coli strains causing neonatal septicaemia and meningitis. 相似文献
7.
8.
Isolated noncompaction of the ventricular myocardium 总被引:6,自引:0,他引:6
Isolated noncompaction of the ventricular myocardium is a recently described anomaly. We report the first case of this anomaly
presenting as a restrictive cardiomyopathy, and the first association of this entity with endocardial fibrosis. 相似文献
9.
Hochegger K Siebenhaar F Vielhauer V Heininger D Mayadas TN Mayer G Maurer M Rosenkranz AR 《European journal of immunology》2005,35(10):3074-3082
Recently, divergent reports on the role of mast cells (MC) in different glomerular diseases have brought our attention to their role in an accelerated model of anti-glomerular basement membrane (GBM) glomerulonephritis (GN). Genetically MC-deficient Kit(W)/Kit(W-v) mice, MC-reconstituted Kit(W)/Kit(W-v) mice and Kit+/+ control mice were subjected to anti-GBM GN. Kit(+/+) mice developed moderate proteinuria and glomerular damage following the induction of anti-GBM nephritis. In contrast, proteinuria and glomerular damage were dramatically increased in MC-deficient Kit(W)/Kit(W-v) mice. MC-reconstituted Kit(W)/Kit(W-v) mice showed proteinuria and glomerular damage comparable to Kit+/+ mice. A significant increase in infiltrating T cells and macrophages was detected in MC-deficient Kit(W)/Kit(W-v) mice as compared to Kit+/+ control mice and MC-reconstituted Kit(W)/Kit(W-v) mice. Accordingly, we observed an increase of TGF-beta1 mRNA in kidneys from Kit(W)/Kit(W-v) mice. Interestingly, we did not detect MC in the kidney using either Giemsa staining or RT-real-time PCR, but MC were found in the regional lymph nodes. Finally, mortality of Kit(W)/Kit(W-v) mice was significantly increased after the induction of anti-GBM GN due to uremia. Our report provides the first direct evidence that MC are protective in anti-GBM GN, possibly by modulating the influx of effector T cells and macrophages to inflammatory sites in the kidney. 相似文献
10.
Mutations in the retinal guanylate cyclase (RETGC-1) gene in dominant cone-rod dystrophy 总被引:3,自引:0,他引:3
Kelsell RE; Gregory-Evans K; Payne AM; Perrault I; Kaplan J; Yang RB; Garbers DL; Bird AC; Moore AT; Hunt DM 《Human molecular genetics》1998,7(7):1179-1184
The dominant cone-rod dystrophy gene CORD6 has previously been mapped to
within an 8 cM interval on chromosome 17p12-p13. The retinal- specific
guanylate cyclase gene (RETGC-1), which maps to within this genetic
interval and previously was implicated in Leber's congenital amaurosis, was
screened for mutations within this family and in a panel of small families
and individuals with various cone and cone- rod dystrophy phenotypes. A
missense mutation (E837D) was identified in affected members of the CORD6
family, as well as a second missense mutation (R838C) in three other
families with dominant cone-rod dystrophy. RETGC-1 is only the fourth gene
to be implicated in cone-rod dystrophy and this is the first report of
dominant mutations in this gene.
相似文献