全文获取类型
收费全文 | 2450篇 |
免费 | 177篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 14篇 |
儿科学 | 146篇 |
妇产科学 | 35篇 |
基础医学 | 301篇 |
口腔科学 | 106篇 |
临床医学 | 202篇 |
内科学 | 440篇 |
皮肤病学 | 30篇 |
神经病学 | 221篇 |
特种医学 | 169篇 |
外国民族医学 | 2篇 |
外科学 | 405篇 |
综合类 | 86篇 |
预防医学 | 158篇 |
眼科学 | 21篇 |
药学 | 113篇 |
中国医学 | 4篇 |
肿瘤学 | 179篇 |
出版年
2021年 | 33篇 |
2020年 | 18篇 |
2019年 | 43篇 |
2018年 | 46篇 |
2017年 | 32篇 |
2016年 | 48篇 |
2015年 | 39篇 |
2014年 | 52篇 |
2013年 | 91篇 |
2012年 | 100篇 |
2011年 | 89篇 |
2010年 | 101篇 |
2009年 | 79篇 |
2008年 | 111篇 |
2007年 | 110篇 |
2006年 | 74篇 |
2005年 | 88篇 |
2004年 | 80篇 |
2003年 | 68篇 |
2002年 | 60篇 |
2001年 | 68篇 |
2000年 | 65篇 |
1999年 | 66篇 |
1998年 | 46篇 |
1997年 | 45篇 |
1996年 | 49篇 |
1995年 | 48篇 |
1994年 | 29篇 |
1993年 | 27篇 |
1992年 | 47篇 |
1991年 | 46篇 |
1990年 | 33篇 |
1989年 | 51篇 |
1988年 | 42篇 |
1987年 | 35篇 |
1986年 | 44篇 |
1985年 | 51篇 |
1984年 | 43篇 |
1983年 | 36篇 |
1982年 | 30篇 |
1981年 | 22篇 |
1980年 | 23篇 |
1979年 | 22篇 |
1978年 | 20篇 |
1976年 | 24篇 |
1975年 | 24篇 |
1974年 | 23篇 |
1973年 | 17篇 |
1970年 | 16篇 |
1967年 | 17篇 |
排序方式: 共有2632条查询结果,搜索用时 0 毫秒
71.
Background
Hydrocele is abnormal collection of serous fluid in the tunica vaginalis or a patent processus vaginalis. It is commonly encountered in our practice and often requires surgical treatment. However in our setting and in many underdeveloped countries, availability of general anaesthetic service is poor due to lack of trained personnel and equipment.Objectives
To ascertain the practicability and acceptability of hydrocelectomy under sedation and local anaesthesia in Nigerian adults with hydrocelePatients and Methods
A prospective study was carried out over a two year period on patients that had hydrocelectomy at the surgery unit of the Obafemi Awolowo University Teaching Hospitals Complex, Wesley Guild Hospital, Ilesa. Consecutive patients with diagnosis of hydrocele who consented had hydrocelectomy using intramuscular diazepam sedation and spermatic-cord block with 0.5% plane xylocaine and the scrotum infiltrated with same along the line of incision.Results
Fifty adult patients were studied: age range 15–94 years. Eighty percent of the patients had unilateral hydrocele and the commonest type was vaginal hydrocele (94%). All patients had hydrocelectomy, 96% were under local anaesthesia while 4% were converted to general anaesthesia. All patients except one prefer to have future surgery under such local anaesthesia and sedation.Conclusion
Hydrocelectomy under local anaesthesia and sedation is practicable and was tolerated and accepted by the adults patients studied. 相似文献72.
Although the dentate gyrus is one of the primary targets of septo-hippocampal cholinergic afferents, relatively little is known about the cholinergic physiology of neurons in the area. By combining whole cell patch-clamp recording with brief local application of exogenous agonists in horizontal slices, we found that there is robust expression of functional somatic alpha 7-containing nicotinic acetylcholine receptors (nAChRs) on molecular layer interneurons, hilar interneurons, and the glutamatergic mossy cells of the dentate hilus. In contrast, the principal neurons of the dentate gyrus, the granule cells, are generally unresponsive to focal somatic or dendritic application of ACh in the presence of atropine. We also demonstrate that cholinergic activation of alpha 7-containing nAChRs on the subgranular interneurons of the hilus can produce methyllycaconitine-sensitive GABAergic inhibitory postsynaptic currents (IPSCs) in nearby granule cells and enhance the amplitude of an electrically evoked monosynaptic IPSC. Further, activation of alpha 7-containing nAChRs on subgranular interneurons that is timed to coincide with synaptic release of glutamate onto these cells will enhance the functional inhibition of granule cells. These findings suggest that a complex interplay between glutamatergic afferents from the entorhinal cortex and cholinergic afferents from the medial septum could be involved in the normal regulation of granule cell function. Such a relationship between these two afferent pathways could be highly relevant to the study of both age-related memory dysfunction and disorders involving regulation of excitability, such as temporal lobe epilepsy. 相似文献
73.
Judith A Hobert Rebecca Embacher Jessica L Mester Thomas W Frazier II Charis Eng 《European journal of human genetics : EJHG》2014,22(2):273-276
Unlike some other childhood neurodevelopmental disorders, no diagnostic biochemical marker has been identified in all individuals with an autism spectrum disorder (ASD). This deficit likely results from genetic heterogeneity among the population. Therefore, we evaluated a subset of individuals with ASDs, specifically, individuals with or without macrocephaly in the presence or absence of PTEN mutations. We sought to determine if amino or organic acid markers could be used to identify individuals with ASDs with or without macrocephaly in the presence or absence of PTEN mutations, and to establish the degree of macrocephaly in individuals with ASDs and PTEN mutation. Urine, blood and occipital–frontal circumference (OFC) measurements were collected from 69 individuals meeting DSM-IV-TR criteria. Urine and plasma samples were subjected to amino and organic acid analyses. PTEN was Sanger-sequenced from germline genomic DNA. Germline PTEN mutations were identified in 27% (6/22) of the macrocephalic ASD population. All six PTEN mutation-positive individuals were macrocephalic with average OFC+4.35 standard deviations (SDs) above the mean. No common biochemical abnormalities were identified in macrocephalic ASD individuals with or without PTEN mutations. In contrast, among the collective ASD population, elevation of urine aspartic acid (87% 54/62), plasma taurine (69% 46/67) and reduction of plasma cystine (72% 46/64) were observed. PTEN sequencing should be carried out for all individuals with ASDs and macrocephaly with OFC ≥2SDs above the mean. A proportion of individuals with ASDs may have an underlying disorder in sulfur amino acid metabolism. 相似文献
74.
Jessica A Kahn Graham Colditz Gideon N Aweh A Lindsay Frazier 《Ambulatory Pediatrics》2002,2(3):212-217
OBJECTIVES: The pelvic examination is an important component of reproductive health services for adolescent girls and is recommended for those who become sexually active. The aims of this study were to describe self-reported rates of pelvic examinations in sexually active adolescent girls and to determine factors associated with having obtained an examination. METHODS: Cross-sectional data from a national self-administered survey of nurses' adolescent daughters were used. Subjects were those girls (N = 635) who reported ever having had sexual intercourse. Bivariate and multivariate analyses were used to identify demographic and psychological variables, preventive health behaviors, and risk behaviors associated with having ever obtained a pelvic examination. RESULTS: Median subject age was 16.0 years (range 12-19 years), and 46% of subjects reported having had a pelvic examination. Variables associated with having obtained an examination were older age (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.09-1.53), cigarette smoking (OR 1.51, 95% CI 1.02-2.24), higher number of sexual partners (OR 1.29, 95% CI 1.14-1.47), and no condom use during last sexual intercourse (OR 1.80, 95% CI 1.19-2.70). CONCLUSIONS: Fewer than half of these sexually active adolescents had ever obtained a pelvic examination. Younger subjects who did not smoke regularly, had fewer partners, and used condoms were less likely to have obtained an examination; these adolescents may not be seeking reproductive health care services or be recognized by parents or providers as being in need of services. 相似文献
75.
76.
Leroy Frazier LaVonne Ortega Nimeshkumar Patel Jamar Barnes Alex E. Crosby Katherine Hempstead 《Journal of the National Medical Association》2017,109(4):272-278
Background
The National Violent Death Reporting System (NVDRS) captures homicides that law enforcement or coroner/medical examiners deem as gang-related but the criteria used may vary across locations. Also, the existing gang-related variable likely underestimates the number of homicides that are associated with gang activity. This study utilizes NVDRS data to identify “gang-like” homicides which are not currently captured as “gang-related.”Methods
A set of criteria recommended by a panel of experts in gang violence, was applied to homicides collected in the NVDRS. These criteria, termed “gang-like” characteristics, were developed in order to better identify homicides consistent with gang activity. The narratives of the identified cases were then reviewed to refine the operational standard. After the reviews were complete, the typology was modified to finalize the operationalization of “gang-like” homicides.Results
A total of 481 gang-like homicides were identified using the “gang-like” criteria. This represents an increase of almost 69% over the 696 gang-related homicides captured in NVDRS dataset.Gang-like and gang-related homicides combined represented 6.6% of homicides that occurred from 2005 to 2008. Among the 16 states included in this analysis, Colorado (15.5%) and Oklahoma (14%) had the highest percentage of homicides that were either gang-related or gang-like.Maryland had the greatest relative increase (227.3%) between gang related and gang-like homicides.Conclusion
The new “gang-like” variable complements the existing “gang-related” variable by providing an automated, standardized way to identify homicides that have circumstances consistent with gang activity. This new variable might be useful to states and localities seeking an efficient way to monitor homicides potentially resulting from gang activity. Additional efforts are needed to standardize the reporting of homicides associated with gang activity. 相似文献77.
Phenotypic and genetic characterization of clinical isolates of CDC coryneform group A-3: proposal of a new species of Cellulomonas, Cellulomonas denverensis sp. nov 下载免费PDF全文
Brown JM Frazier RP Morey RE Steigerwalt AG Pellegrini GJ Daneshvar MI Hollis DG McNeil MM 《Journal of clinical microbiology》2005,43(4):1732-1737
CDC coryneform group A-3 bacteria are rare human pathogens. In this study, six group A-3 isolates (two from blood, one from cerebrospinal fluid, and one each from homograft valve, lip wound, and pilonidal cyst) were compared to the type strains of phenotypically related organisms, Cellulomonas fimi, Cellulomonas hominis, Oerskovia turbata, and Sanguibacter suarezii, and characterized by phenotypic, chemotaxonomic, and genotypic studies. DNA-DNA reassociation analysis identified two genomic groups, and phylogenetic analysis of the 16S rRNA gene sequence identified the taxonomic positions of these groups to genus level. Two groups were defined, and both were more closely related to Cellulomonas species: one group of three strains, for which we propose the new species Cellulomonas denverensis sp. nov., with the type strain W6929 (ATCC BAA-788(T) or DSM 15764(T)), was related to C. hominis ATCC 51964(T) (98.5% 16S rRNA gene sequence similarity), and the second group of three strains was related to C. hominis ATCC 51964(T) (99.8 to 99.9% 16S rRNA gene sequence similarity). The definition of this new Cellulomonas species and the confirmation of three strains as C. hominis serve to further clarify the complex taxonomy of CDC coryneform group A-3 bacteria and will assist in our understanding of the epidemiology and clinical significance of these microorganisms. 相似文献
78.
Positional cloning of the gene for X-linked retinitis pigmentosa 3: homology with the guanine-nucleotide-exchange factor RCC1 总被引:6,自引:7,他引:6
Roepman R; van Duijnhoven G; Rosenberg T; Pinckers AJ; Bleeker-Wagemakers LM; Bergen AA; Post J; Beck A; Reinhardt R; Ropers HH; Cremers FP; Berger W 《Human molecular genetics》1996,5(7):1035-1041
The gene for retinitis pigmentosa 3 (RP3), the most frequent form of X-
linked RP (XLRP), has been mapped previously to a chromosome interval of
less than 1000 kbp between the DXS1110 marker and the OTC locus at
Xp21.1-p11.4. Employing a novel technique, YAC Representation Hybridization
(YRH)', we have recently identified a small XLRP associated microdeletion
in this interval, as well as several putative exons including the 3' end of
a gene that was truncated by the deletion. cDNA library screening and
sequencing of a cosmid centromeric to the deletion has now enabled us to
identify numerous additional exons and to detect several point mutations in
patients with XLRP. The predicted gene product shows homology to RCC1, the
guanine-nucleotide- exchange factor (GEF) of the Ras-like GTPase Ran. Our
findings suggest that we have cloned the long-sought RP3 gene, and that it
may encode the GEF of a retina-specific GTP-binding protein.
相似文献
79.
80.