全文获取类型
收费全文 | 641篇 |
免费 | 23篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 43篇 |
妇产科学 | 83篇 |
基础医学 | 55篇 |
口腔科学 | 9篇 |
临床医学 | 54篇 |
内科学 | 178篇 |
皮肤病学 | 12篇 |
神经病学 | 4篇 |
特种医学 | 131篇 |
外科学 | 23篇 |
综合类 | 11篇 |
一般理论 | 1篇 |
预防医学 | 20篇 |
眼科学 | 2篇 |
药学 | 22篇 |
1篇 | |
中国医学 | 6篇 |
肿瘤学 | 17篇 |
出版年
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 5篇 |
2014年 | 11篇 |
2013年 | 18篇 |
2012年 | 13篇 |
2011年 | 11篇 |
2010年 | 30篇 |
2009年 | 22篇 |
2008年 | 16篇 |
2007年 | 23篇 |
2006年 | 18篇 |
2005年 | 9篇 |
2004年 | 16篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 24篇 |
2000年 | 13篇 |
1999年 | 16篇 |
1998年 | 29篇 |
1997年 | 30篇 |
1996年 | 42篇 |
1995年 | 37篇 |
1994年 | 34篇 |
1993年 | 23篇 |
1992年 | 6篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 18篇 |
1988年 | 26篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1973年 | 2篇 |
1965年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有673条查询结果,搜索用时 15 毫秒
1.
The recent Confidential Enquiry (2000-2002) has emphasised 'emergency drills for maternal resuscitation should be regularly practised in clinical areas in all maternity units'. It was therefore planned to assess the knowledge of airway management and ventilation among obstetrics and gynaecology trainees in the Yorkshire Deanery (Training Region). Questionnaires were given to trainees attending the Modular Training Programme and were collected on the same day. A total of 71 questionnaires were collected which represents 62% of the 113 trainees in Yorkshire region. Replies were received from 39 registrars, 27 Senior House Officers (SHO), four Senior SHOs (SSHO) and one clinical fellow. MRCOG Part 1 was passed by 52% and 36% of trainees had MRCOG Part 2. A total of 69% of trainees did not know that chin lift opens the airway in some 70 - 80% of patients; 50% of trainees were not aware why jaw thrust is preferred over chin lift; 76% of the trainees knew the most common cause of airway obstruction in a patient with an altered level of consciousness--the tongue falls back and obstructs the pharynx ('swallowing the tongue'). Knowledge of the main cause of airway obstruction was good among obstetrics and gynaecology trainees, but their understanding of how to manage this was found to be relatively poor. Attendance at a local Basic Life Support course should be compulsory for obstetric and gynaecology trainees early in their career. 相似文献
2.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
3.
4.
The Hantaan virus glycoprotein precursor is cleaved at the conserved pentapeptide WAASA. 总被引:10,自引:0,他引:10
The medium segment of the tripartite negative-stranded RNA genome of hantaviruses encodes for the predicted glycoprotein precursor GPC. We have demonstrated here the expression of the glycoprotein precursor of Hantaan virus following transfection of mammalian cells. The cleavage of the precursor into the glycoproteins G1 and G2 followed the rules for signal peptides and seemed to occur directly at the pentapeptide motif "WAASA." Our data indicate that the signal peptidase complex is responsible for the proteolytic processing of the precursor GPC of Hantaan virus. The comparison of this region of the glycoprotein precursor, including the absolutely conserved WAASA motif, suggests a similar cleavage event for all hantavirus glycoproteins. 相似文献
5.
Detection of chromosomes and estimation of aneuploidy in human spermatozoa using fluorescence in-situ hybridization 总被引:11,自引:0,他引:11
The development and application of fluorescence in-situ hybridization
(FISH) has opened the way for comprehensive studies on numerical chromosome
abnormalities in human spermatozoa. FISH can be rapidly applied to large
numbers of spermatozoa and thus overcomes the major limitation of
karyotyping spermatozoa after penetration of zona-free hamster oocytes. The
simultaneous hybridization of two or more chromosome-specific probes to
spermatozoa and subsequent detection of the bound probes using different
fluorescent detection systems enables two or more chromosomes to be
localized simultaneously in the same spermatozoon and provides a technique
for undertaking reasonable estimates of aneuploidy. The most commonly used
probes are those which bind to the centromeric region of specific
chromosomes. Most studies to date have concentrated on estimating
aneuploidy in spermatozoa from normospermic men, although reports are
beginning to appear on aneuploidy in spermatozoa from subfertile and
infertile men. Multi- probe FISH studies have generally reported disomy
(hyperhaploidy) estimates of 0.05-0.2% per chromosome. There is preliminary
evidence that some chromosomes such as X, Y and 21 are predisposed towards
higher rates of non-disjunction during spermatogenesis. There are also
suggestions of inter-donor variability in aneuploidy frequencies for
specific chromosomes, although this requires confirmation in larger
studies. While FISH is clearly a powerful technique that has many
applications in reproductive medicine, it must also be realized that it
does have limitations and the technology itself is still evolving and has
yet to be fully validated on spermatozoa.
相似文献
6.
7.
Debelenko LV; Brambilla E; Agarwal SK; Swalwell JI; Kester MB; Lubensky IA; Zhuang Z; Guru SC; Manickam P; Olufemi SE; Chandrasekharappa SC; Crabtree JS; Kim YS; Heppner C; Burns AL; Spiegel AM; Marx SJ; Liotta LA; Collins FS; Travis WD; Emmert-Buck MR 《Human molecular genetics》1997,6(13):2285-2290
Lung carcinoids occur sporadically and rarely in association with multiple
endocrine neoplasia type 1 (MEN1). There are no well defined genetic
abnormalities known to occur in these tumors. We studied 11 sporadic lung
carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene
on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy
fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was
studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene
were inactivated. All four tumors showed the presence of a MEN1 gene
mutation and loss of the other allele. Observed mutations included a 1 bp
insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide
substitution affecting a donor splice site. Each mutation predicts
truncation or potentially complete loss of menin. The remaining seven
tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH.
The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a
complex germline MEN1 gene mutation. The data implicate the MEN1 gene in
the pathogenesis of sporadic lung carcinoids, representing the first
defined genetic alteration in these tumors.
相似文献
8.
9.
A prospective study of methylenetetrahydrofolate reductase and methionine synthase gene polymorphisms, and risk of colorectal adenoma 总被引:8,自引:2,他引:8
Chen J; Giovannucci E; Hankinson SE; Ma J; Willett WC; Spiegelman D; Kelsey KT; Hunter DJ 《Carcinogenesis》1998,19(12):2129-2132
We examined the relationship between a functional polymorphism (667C--
>T, ala-->val) of the methylenetetrahydrofolate reductase gene
(MTHFR) and the risk of colorectal adenomas in the prospective Nurses'
Health Study. Among 257 incident polyp cases and 713 controls, the MTHFR
val/val polymorphism [relative risk (RR) = 1.35, 95% confidence interval
(CI) 0.84-2.17] was not significantly associated with risk of adenomas.
This lack of association was observed for both small (RR = 1.36, 95% CI
0.76-2.45) and large (RR = 1.32, 95% CI 0.66-2.66) adenomas. Furthermore,
there was no significant interaction between this polymorphism and
consumption of either folate, methionine or alcohol. We also examined the
relationship of a newly identified polymorphism (asp919gly) of the
methionine synthase gene (MS) with the risk of colorectal adenomas in the
same population. The MS gly/gly polymorphism was also not significantly
associated with risk of colorectal adenomas (RR = 0.66, 95% CI 0.26-1.70).
These results, which need to be confirmed in other studies, suggest that
the MTHFR val/val polymorphism, which has been previously inversely
associated with risk of colorectal cancer, plays a role only in a late
stage (adenoma-- >carcinoma) of colorectal tumorigenesis, and/or may
protect against malignant transformation in the subset of benign adenomas,
which may progress to malignancy.
相似文献
10.