全文获取类型
收费全文 | 793篇 |
免费 | 27篇 |
国内免费 | 14篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 8篇 |
妇产科学 | 1篇 |
基础医学 | 89篇 |
口腔科学 | 8篇 |
临床医学 | 148篇 |
内科学 | 93篇 |
皮肤病学 | 8篇 |
神经病学 | 17篇 |
特种医学 | 74篇 |
外科学 | 55篇 |
综合类 | 5篇 |
预防医学 | 17篇 |
眼科学 | 234篇 |
药学 | 45篇 |
肿瘤学 | 30篇 |
出版年
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2014年 | 19篇 |
2013年 | 30篇 |
2012年 | 17篇 |
2011年 | 23篇 |
2010年 | 18篇 |
2009年 | 15篇 |
2008年 | 24篇 |
2007年 | 42篇 |
2006年 | 36篇 |
2005年 | 23篇 |
2004年 | 43篇 |
2003年 | 35篇 |
2002年 | 49篇 |
2001年 | 56篇 |
2000年 | 43篇 |
1999年 | 27篇 |
1998年 | 13篇 |
1997年 | 15篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 30篇 |
1991年 | 20篇 |
1990年 | 7篇 |
1989年 | 17篇 |
1988年 | 14篇 |
1987年 | 21篇 |
1986年 | 23篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1977年 | 4篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1971年 | 3篇 |
1970年 | 3篇 |
1968年 | 3篇 |
1967年 | 4篇 |
排序方式: 共有834条查询结果,搜索用时 31 毫秒
1.
2.
1-乙基-6-氟-1,4-二氢-4-氧代-7-(4-芳酰硫代氨甲酰基-1-哌嗪基)-3-喹啉羧酸的合成及抗菌作用 总被引:4,自引:1,他引:3
Thirteen new 1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(4-aroyl-thiocarbamoyl- 1 piperazinyl)-3-quinoline carboxylic acids were prepared, Their structures were characterized by elemental analysis, IR, HNMR and MS spectra.Preliminary pharmacological tests indicated that some of compounds Ia~m possess strong inhibiting activity against Escherichia coli, Bacillus subtilis and Proteus at concentration of 100 μg/ml. 相似文献
3.
4.
5.
Posterior chamber intraocular lenses in a series of 75 autopsy eyes. Part I: Loop location 总被引:1,自引:0,他引:1
D J Apple S B Park K H Merkley R N Brems S C Richards K E Langley K L Piest R A Isenberg 《Journal of cataract and refractive surgery》1986,12(4):358-362
Over a period of 27 months, November 1983 to February 1986, 75 eyes obtained postmortem with posterior chamber intraocular lenses (IOLs) were examined at the Center for Intraocular Lens Research, University of Utah Health Sciences Center. These IOLs were studied by histopathological techniques to determine the location of the loops. The most common combination, found in 47% of the specimens, was one loop in the lens capsular sac (bag) and one loop in the ciliary sulcus. In 32% of the specimens, both loops were in the capsular sac; in 17%, both loops were in the ciliary sulcus. Compared to results observed in other autopsy studies, in which capsular fixation was documented in less than 3% of cases, these findings reflect a trend toward capsular sac (in-the-bag) implantation of open-looped posterior chamber IOLs. 相似文献
6.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2
7.
Desmond FS Cormack RMN RGN MPhil DipEd PhD DipN Honorary Reader in Health Nursing William Reynolds RMN RNT RGN MPhil Senior Tutor 《Journal of advanced nursing》1992,17(12):1472-1478
Arguably, nursing, like all health care disciplines, is an applied science. Essentially, this refers to the application of theory in order to understand and respond to the health problems of clients. These theories may be drawn (borrowed) from any applied science, or generated inductively from clinical nursing practice. Alternatively, nurses may attempt to apply deductive theory (global theoretical frameworks) known as nursing models. In this paper, all theoretical approaches, irrespective of origin, are referred to as models used by nurses. Thirteen criteria by which clinicians, and others, can evaluate the clinical and practical utility of models used by nurses which are expressed in the form of questions are identified and discussed. The criteria are an extension, both in detail and in number, of those developed by Reynolds and Cormack and subsequently applied by those writers to the Johnson Behavioural System Model of Nursing. The value, or otherwise, of individual models, or of models in general, will not be discussed in this paper. However, the authors propose that if the evaluation criteria described here are applied to existing models, serious deficits will be identified in relation to their clinical and practical utility. 相似文献
8.
Gravitt PE Peyton CL Alessi TQ Wheeler CM Coutlée F Hildesheim A Schiffman MH Scott DR Apple RJ 《Journal of clinical microbiology》2000,38(1):357-361
Genital human papillomaviruses (HPVs) are commonly detected from clinical samples by consensus PCR methods. Two commonly used primer systems, the MY09-MY11 (MY09/11) primers and the GP5+-GP6+ (GP5+/6+) primers, amplify a broad spectrum of HPV genotypes, but with various levels of sensitivity among the HPV types. Analysis of the primer-target sequence homology for the MY09/11 primers showed an association between inefficient amplification of HPV types and the number and position of mismatches, despite accommodation of sequence variation by inclusion of degenerate base sites. The MY09/11 primers were redesigned to increase the sensitivity of amplification across the type spectrum by using the same primer binding regions in the L1 open reading frame. Sequence heterogeneity was accommodated by designing multiple primer sequences that were combined into an upstream pool of 5 oligonucleotides (PGMY11) and a downstream pool of 13 oligonucleotides (PGMY09), thereby avoiding use of degenerate bases that yield irreproducible primer syntheses. The performance of the PGMY09-PGMY11 (PGMY09/11) primer system relative to that of the standard MY09/11 system was evaluated with a set of 262 cervicovaginal lavage specimens. There was a 91.5% overall agreement between the two systems (kappa = 0.83; P < 0.001). The PGMY09/11 system appeared to be significantly more sensitive than the MY09/11 system, detecting an additional 20 HPV-positive specimens, for a prevalence of 62.8% versus a prevalence of 55.1% with the MY09/11 system (McNemar's chi(2) = 17.2; P < 0.001). The proportion of multiple infections detected increased with the PGMY09/11 system (40. 0 versus 33.8% of positive infections). HPV types 26, 35, 42, 45, 52, 54, 55, 59, 66, 73, and MM7 were detected at least 25% more often with the PGMY09/11 system. The PGMY09/11 primer system affords an increase in type-specific amplification sensitivity over that of the standard MY09/11 primer system. This new primer system will be useful in assessing the natural history of HPV infections, particularly when the analysis requires HPV typing. 相似文献
9.
Wu AH Holtman V Apple FS Ricchiuti V DiBello PM Jacobsen D 《Annals of clinical and laboratory science》2000,30(2):185-190
A fully automated immunoassay for total plasma homocysteine assay was evaluated at four centers. To measure total homocysteine, oxidized forms of homocysteine in serum and plasma were reduced by dithiothreitol and assayed by a competitive fluorescence polarization technique. The assay had within-run precision from 0.9 to 3.0% and total precision from 2.8 to 4.1% for control materials with homocysteine concentrations of approximately 7, 12.5, and 25 micromol/L, a sensitivity of 0.35 micromol/L, good parallelism upon dilution, and analytical recovery ranging from 97.4 to 103.8%. The immunoassay correlated with four different HPLC assays for homocysteine, yielding a slope of 0.98, an intercept of -0.19 micromol/L, and a correlation coefficient of 0.966 for 440 paired samples. The reference range, determined with plasma samples from 609 males and 600 females, yielded a mean of 9.17+/-2.86 micromol/L, with a central 95% range of 4.78-15.43 micromol/L. The immunoassay is a suitable alternative to HPLC and may be useful in screening persons with high risk of coronary artery disease. 相似文献
10.
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