全文获取类型
收费全文 | 1289篇 |
免费 | 99篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 50篇 |
妇产科学 | 23篇 |
基础医学 | 190篇 |
口腔科学 | 54篇 |
临床医学 | 112篇 |
内科学 | 299篇 |
皮肤病学 | 15篇 |
神经病学 | 42篇 |
特种医学 | 36篇 |
外科学 | 138篇 |
综合类 | 33篇 |
一般理论 | 1篇 |
预防医学 | 100篇 |
眼科学 | 92篇 |
药学 | 69篇 |
中国医学 | 3篇 |
肿瘤学 | 128篇 |
出版年
2023年 | 7篇 |
2022年 | 18篇 |
2021年 | 46篇 |
2020年 | 26篇 |
2019年 | 27篇 |
2018年 | 29篇 |
2017年 | 25篇 |
2016年 | 40篇 |
2015年 | 38篇 |
2014年 | 48篇 |
2013年 | 71篇 |
2012年 | 98篇 |
2011年 | 85篇 |
2010年 | 58篇 |
2009年 | 41篇 |
2008年 | 73篇 |
2007年 | 73篇 |
2006年 | 83篇 |
2005年 | 55篇 |
2004年 | 43篇 |
2003年 | 54篇 |
2002年 | 54篇 |
2001年 | 35篇 |
2000年 | 16篇 |
1999年 | 17篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 16篇 |
1991年 | 13篇 |
1990年 | 17篇 |
1989年 | 20篇 |
1988年 | 9篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 8篇 |
1984年 | 7篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 6篇 |
1930年 | 4篇 |
1929年 | 5篇 |
排序方式: 共有1393条查询结果,搜索用时 15 毫秒
1.
2.
Ramanathan Sundar Varma Shashi Kumar Rao Kolli Madhusudana Muralidharan Srinivasan 《Indian Journal of Thoracic and Cardiovascular Surgery》2004,20(4):164-166
Background Extended trans septal (ETS) approach for mitral valve surgery often divides the artery to the Sino-Atrial node. The clinical
implication of this is contentious. We analyzed our early results with ETS approach.
Methods Between June 1998 and September 2003 eleven patients underwent mitral valve surgery by ETS approach. Six were females. Age
ranged from 19 years to 67 years (median 40 years). Six underwent mitral valve replacement (MVR). Four underwent aortic and
mitral (double) valve replacement (DVR). One had mitral valve repair. Three had additional procedures (tricuspid valve repair=1,
Coronary artery bypass=1, Aorto bifemoral graft=1). Cardiopulmonary bypass ranged from 64 minutes to 77 minutes (median 72
minutes) for MVR and 112 minutes to 178 minutes (median 140 minutes) for DVR. Aortic cross clamp times ranged from 39 minutes
to 52 minutes (median 47 minutes) for MVR and 74 minutes to 120 minutes (median 95 minutes) for DVR.
Results There was no mortality or morbidity attributed to the ETS approach. One early death in emergency DVR was due to heart failure.
Three patients needed seqeuntial pacing in the immediate post-operative period. Nine out of ten survivors were back to their
preoperative rhythms on hospital discharge (6 sinus rhythm; 3 atrial fibrillation). One patient with preoperative trifascicular
block who underwent reoperation to fix a paravalvular mitral leak needed a permanent pacemaker (VVI). The follow-up ranged
from 1 month to 64 months (median 6 months) and is 100% complete. There was no late death or new arrhythmia.
Conclusions Extended trans septal approach is safe. It gives excellent exposure of the mitral valve. division of the sinus node artery
is not deleterious in the short to intermediate term.
Presented at the 50th Annual Meeting of IACTS. New Delhi, Feb. 2004. 相似文献
3.
4.
Chakraborty S Garg P Ramamurthy T Thungapathra M Gautam JK Kumar C Maiti S Yamasaki S Shimada T Takeda Y Ghosh A Nair GB 《Journal of medical microbiology》2001,50(10):879-888
This study identified 17 matching serogroups of Vibrio cholerae belonging to serogroups other than O1 and O139 isolated from human cases and from the environment during a concurrent clinical and environmental study conducted in Calcutta, a cholera endemic area. Isolates within these matching serogroups were compared by various phenotypic and genotypic traits to determine if the environment was the source of the organisms associated with the disease. Clinical strains of V. cholerae were resistant to a greater number of drugs and exhibited multi-drug resistance compared with their environmental counterparts. Except for the presence of the genes for the El Tor haemolysin and the regulatory element ToxR in most of the strains of V. cholerae examined, non-O1, non-O139 V. cholerae strains lacked most of the other known virulence traits associated with toxigenic V. cholerae O1 or O139. Restriction fragment-length polymorphism of virulence-associated genes, ribotypes and DNA fingerprints of strains of matched serogroups showed considerable diversity, although some gene polymorphisms and ribotypes of a few strains of different serogroups were similar. It is concluded that despite sharing the same serogroup, environmental and clinical isolates were genetically heterogeneous and were of different lineages. 相似文献
5.
Sequence Analysis of the RNA Polymerase Gene of Foot-and-Mouth Disease Virus Serotype Asia1 总被引:1,自引:0,他引:1
George M Venkataramanan R Pattnaik B Sanyal A Gurumurthy CB Hemadri D Tosh C 《Virus genes》2001,22(1):21-26
The complete nucleotide (nt.) sequence of the RNA polymerase (3D) gene and 81 nt. in the 3-untranslated region of foot-and-mouth disease virus (FMDV) serotype Asia1 (IND63/72) was determined and compared with the sequence of other FMDV serotypes. The 3D genomic region was 1410 nt. long encoding 470 amino acids with an inframe stop codon (TAA) at nt. position 1411–1413. The deduced amino acid sequence of the protein showed 8 conserved motifs as reported in other picornaviruses, 2 of which are 100% identical across the serotypes. Antigenic regions in the polymerase protein were predicted and found to be located at the N-terminus of the protein. The phylogenetic analysis showed that the FMD viruses were segregated into different clusters based on geographical origin; the Asia1 virus did not cluster tightly with any of the geographical groups. 相似文献
6.
Evaluation of DNA probes for specific detection of Vibrio cholerae O139 Bengal. 总被引:2,自引:3,他引:2
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
G B Nair P K Bag T Shimada T Ramamurthy T Takeda S Yamamoto H Kurazono Y Takeda 《Journal of clinical microbiology》1995,33(8):2186-2187
Two DNA probes, 2R1 and 2R3, prepared from a region in the chromosome specific for the lipopolysaccharide O side chains of Vibrio cholerae O139 (M.K. Waldor and J.J. Mekalanos, Lancet 343:1366, 1994) were examined for their specificity and sensitivity. Both probes did not hybridize with any strain of V. cholerae belonging to serogroups other than O139 and to any of the other species examined belonging to the family Vibrionaceae. Among the 126 strains of V. cholerae O139 examined, probe 2R1 hybridized with 125 strains while probe 2R3 hybridized with all 126 strains. Both probes were found to be highly specific and sensitive and can be used for the specific identification of V. cholerae O139. 相似文献
7.
8.
9.
Tetracycline administration restores osteoblast structure and function during experimental diabetes. 总被引:2,自引:0,他引:2
Osteopenia is a recognized complication of diabetes mellitus in humans and experimental animals. We recently found that tetracyclines prevent osteopenia in the streptozotocin-induced diabetic rat and that this effect was associated with a restoration of defective osteoblast morphology (Golub et al., 1990). The present study extends these initial ultrastructural observations by assessing osteoblast function in the untreated and tetracycline-treated diabetic rats. After a 3-week protocol, non-diabetic control and diabetic rats, including those orally administered a tetracycline, minocycline (MC), or a non-antimicrobial tetracycline analog (CMT), were perfusion-fixed with an aldehyde mixture; the humeri were dissected and processed for ultracytochemical localization of alkaline phosphatase (ALPase) and Ca-ATPase activities. Some rats from each experimental group received an intravenous injection of 3H-proline as a radioprecursor of procollagen, and the humeri were processed for light microscopic autoradiography. In addition, the osteoid volume in each experimental group was quantitatively examined by morphometric analysis of electron micrographs. During the diabetic state, active cuboidal osteoblasts in the endosteum of control rats were replaced by flattened bone-lining cells that contained few cytoplasmic organelles for protein synthesis (Golgi-RER system), and active transport (mitochondria). Treating diabetic rats with MC, and even more so with CMT, appeared to "restore" osteoblast structure. During diabetes, bone-lining cells incorporated little 3H-proline or secreted little labeled protein and produced only a very thin osteoid layer. Tetracycline administration to the diabetics increased both the incorporation of 3H-proline by osteoblasts and their secretion of labeled protein toward the osteoid matrix, in a pattern similar to that seen in the non-diabetic controls.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
10.
Wilkie SE Newbold RJ Deery E Walker CE Stinton I Ramamurthy V Hurley JB Bhattacharya SS Warren MJ Hunt DM 《Human molecular genetics》2000,9(20):3065-3073
Three different mutations in codon 838 of GUCY2D, the gene for retinal guanylate cyclase 1, have been linked to autosomal dominant cone-rod dystrophy at the CORD6 locus. To examine the relationship between enzyme activity and disease severity, the three disease-causing substitutions (R838C, R838H and R838S) and four artificial mutations (R838A, R838E, R838L and R838K) were generated. Assay of GCAP1-stimulated cyclase activity in vitro shows that, compared with wild-type, R838E, R838L and R838K possess only low activity, whereas R838A, R838C, R838H and R838S have activity equal or superior to wild-type at low Ca(2+) concentrations. These four latter mutants showed a higher apparent affinity for GCAP1 than did wild-type. The Ca(2+) sensitivity of the GCAP1 activation was also altered with marked residual activity at high Ca(2+), the effect increasing: wild-type < R838C < R838H < R838A < R838S. Within the photoreceptor, this would result in a failure to inactivate cyclase activity at high physiological Ca(2+ )concentrations. Amongst the three disease-associated mutations, the effect correlates directly with disease severity. The wild-type and R838H mutant displayed a difference in pH sensitivity, with the mutant showing a higher specific activity with pH > 6.0. Site 838 is in the dimerization domain that forms a coiled-coil in the active protein. A computer-aided structure prediction of this region indicates that R838 in the wild-type breaks the structure at four helical turns, and there is an increasing tendency for the structure to continue for further turns in the order R838C < R838H,S,K < R838E < R838A < R838L. 相似文献