全文获取类型
收费全文 | 4685篇 |
免费 | 428篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 116篇 |
妇产科学 | 120篇 |
基础医学 | 605篇 |
口腔科学 | 89篇 |
临床医学 | 620篇 |
内科学 | 1031篇 |
皮肤病学 | 38篇 |
神经病学 | 391篇 |
特种医学 | 118篇 |
外科学 | 410篇 |
综合类 | 171篇 |
一般理论 | 8篇 |
预防医学 | 588篇 |
眼科学 | 49篇 |
药学 | 395篇 |
中国医学 | 10篇 |
肿瘤学 | 321篇 |
出版年
2022年 | 32篇 |
2021年 | 87篇 |
2020年 | 58篇 |
2019年 | 81篇 |
2018年 | 87篇 |
2017年 | 55篇 |
2016年 | 60篇 |
2015年 | 81篇 |
2014年 | 102篇 |
2013年 | 171篇 |
2012年 | 218篇 |
2011年 | 261篇 |
2010年 | 118篇 |
2009年 | 121篇 |
2008年 | 219篇 |
2007年 | 250篇 |
2006年 | 246篇 |
2005年 | 266篇 |
2004年 | 231篇 |
2003年 | 201篇 |
2002年 | 229篇 |
2001年 | 154篇 |
2000年 | 142篇 |
1999年 | 134篇 |
1998年 | 52篇 |
1997年 | 56篇 |
1996年 | 35篇 |
1995年 | 49篇 |
1994年 | 30篇 |
1992年 | 69篇 |
1991年 | 94篇 |
1990年 | 54篇 |
1989年 | 78篇 |
1988年 | 83篇 |
1987年 | 91篇 |
1986年 | 61篇 |
1985年 | 69篇 |
1984年 | 57篇 |
1983年 | 36篇 |
1982年 | 29篇 |
1979年 | 41篇 |
1978年 | 27篇 |
1977年 | 26篇 |
1975年 | 25篇 |
1974年 | 31篇 |
1973年 | 41篇 |
1972年 | 31篇 |
1971年 | 30篇 |
1970年 | 29篇 |
1969年 | 29篇 |
排序方式: 共有5117条查询结果,搜索用时 15 毫秒
31.
32.
Dr. J. H. T. Bates G. N. Maksym D. Navajas B. Suki 《Annals of biomedical engineering》1994,22(6):674-681
The mechanical properties of lung tissue are important contributors to both the elastic and dissipative properties of the
entire organ at normal breathing frequencies. A number of detailed studies have shown that the stress adaptation in the tissue
of the lung following a step change in volume is very accurately described by the functiont
−k for some small positive constantk. We applied step increases in length to lung parenchymal strips and found the ensuing stress recovery to be extremely accurately
described byt
−k over almost 3 decades of time, despite the quasi-static stress-length characteristics of the strips being highly nonlinear.
The corresponding complex impedance of lung tissue was found to have a magnitude that varied inversely with frequency. We
note that this is highly reminiscent of a phenomenon known as 1/f noise, which has been shown to occur ubiquitously throughout the natural world. 1/f noise has been postulated to be a reflection of the complexity of the system that produces it, something like a central limit
theorem for dynamic systems. We have therefore developed the hypothesis that thet
−k
nature of lung tissue stress adaptation follows from the fact that lung tissue itself is composed of innumerable components
that interact in an extremely rich and varied manner. Thus, although the constantk is no doubt determined by the particular constituents of the tissue, we postulate that the actual functional form of the
stress adaptation is not. 相似文献
33.
Filamentous actin bundles in the kidney 总被引:2,自引:0,他引:2
The distribution of filamentous actin bundles in the rat kidney was studied using a fluorescent phallotoxin label and transmission electron microscopy. The microvillous brush border lining proximal tubules, smooth muscle in renal vessels, and renal corpuscles were the structures most intensely labeled with rhodamine phalloidin. Closer evaluation of renal corpuscles revealed intense labeling of filamentous actin within podocyte foot processes enveloping the glomerular capillary loops. Rhodamine phalloidin also labeled basal bands of filamentous actin in the parietal epithelium and basal bands of actin in proximal and distal tubules. Finally, a band of filamentous actin was evident along the innermost aspect of the kidney capsule, within cells which often joined to form sinus-like compartments. 相似文献
34.
35.
Evaluation of method for secondary DNA typing of Mycobacterium tuberculosis with pTBN12 in epidemiologic study of tuberculosis. 总被引:1,自引:1,他引:1
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)
Z Yang F Chaves P F Barnes W J Burman J Koehler K D Eisenach J H Bates M D Cave 《Journal of clinical microbiology》1996,34(12):3044-3048
Secondary fingerprinting of Mycobacterium tuberculosis DNA with a probe containing the polymorphic GC-rich repetitive sequence present in pTBN12 has been found to have greater discriminating power than does fingerprinting with the insertion sequence IS6110 for strains carrying few copies of IS6110. To validate the use of pTBN12 fingerprinting in the molecular epidemiology of tuberculosis, M. tuberculosis isolates from 67 patients in five states in the United States and in Spain were fingerprinted with both IS6110 and pTBN12. Epidemiologic links among the 67 patients were evaluated by patient interview and/or review of medical records. The 67 isolates had 5 IS6110 fingerprint patterns with two to five copies of IS6110 and 18 pTBN12 patterns, of which 10 were shared by more than 1 isolate. Epidemiologic links are consistently found among patients whose isolates had identical pTBN12 patterns, whereas no links were found among patients whose isolates had unique pTBN12 patterns. This suggests that pTBN12 fingerprinting is a useful tool to identify epidemiologically linked tuberculosis patients whose isolates have identical IS6110 fingerprints containing fewer than six fragments. 相似文献
36.
Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains 总被引:6,自引:2,他引:6
Flint J; Bates GP; Clark K; Dorman A; Willingham D; Roe BA; Micklem G; Higgs DR; Louis EJ 《Human molecular genetics》1997,6(8):1305-1313
We have sequenced and compared DNA from the ends of three human
chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are
subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub-
domains with entirely different patterns of homology to other chromosome
ends. The distal regions contain numerous, short (<2 kb) segments of
interrupted homology to many other human telomeric regions. The proximal
regions show much longer (approximately 10-40 kb) uninterrupted homology to
a few chromosome ends. A comparison of all yeast subtelomeric regions
indicates that they too are subdivided by degenerate TTAGGG repeats into
distal and proximal sub-domains with similarly different patterns of
identity to other non-homologous chromosome ends. Sequence comparisons
indicate that the distal and proximal sub-domains do not interact with each
other and that they interact quite differently with the corresponding
regions on other, non- homologous, chromosomes. These findings suggest that
the degenerate TTAGGG repeats identify a previously unrecognized,
evolutionarily conserved boundary between remarkably different subtelomeric
domains.
相似文献
37.
Origin and filiation of human plasmacytoid dendritic cells 总被引:8,自引:0,他引:8
Brière F Bendriss-Vermare N Delale T Burg S Corbet C Rissoan MC Chaperot L Plumas J Jacob MC Trinchieri G Bates EE 《Human immunology》2002,63(12):1081-1093
Human plasmacytoid dendritic cells represent a rare population of leukocytes which produce high amounts of type I interferon in response to certain viruses. Although those cells were first described in 1958, there are still unsolved issues related to their origin and function. Recently, a leukemic counterpart of plasmacytoid dendritic cells was identified. Molecular approaches using either normal or leukemic plasmacytoid dendritic cells provide some new insights into the controversial lymphoid origin of those cells. The need for specific markers is still a critical aspect for the identification of plasmacytoid dendritic cells, whatever stage of differentiation, in normal as well as in pathological conditions. Hopefully, novel markers will allow delineation of the relationships between dendritic cells at different stages of differentiation/maturation along the myeloid and lymphoid lineages. 相似文献
38.
Voxel-based lesion-symptom mapping 总被引:5,自引:0,他引:5
Bates E Wilson SM Saygin AP Dick F Sereno MI Knight RT Dronkers NF 《Nature neuroscience》2003,6(5):448-450
39.
A colorimetric enzyme amplification system was used to develop an immunoassay for human calcitonin (hCT) with a sensitivity of 6 pmol/l, and intra- and inter-assay CVs of 12% and 11.8% respectively for the low pool, and 10% and 11.2% for the high pool. The mean recovery of added synthetic hCT (58.5 pmol) from the plasma of 10 patients was 110% (64.4 pmol). The correlation coefficient between radioimmunoassay (RIA) and amplified enzymo-immunoassay was found to be 0.96 (p 0.001). The assay was successfully applied to the measurement of elevated calcitonin levels in plasma from patients with medullary carcinoma of the thyroid (MCT). AEIA offered a reliable and sensitive alternative to RIA for calcitonin determination with the added advantage of convenience as the label employed was much more stable. 相似文献
40.
Tapsall JW Shultz T Limnios E Munro R Mercer J Porritt R Griffith J Hogg G Lum G Lawrence A Hansman D Collignon P Southwell P Ott K Gardam M Richardson CJ Bates J Murphy D Smith H;National Neisseria Network of Australia 《Pathology》2001,33(3):359-361
A total of 1434 strains of Neisseria meningitidis isolated from cases of invasive meningococcal disease (IMD) in Australia between 1994 and 1999 were examined by standard methods for susceptibility to antibiotics used for treatment and prophylaxis. The proportion of isolates fully susceptible to penicillin decreased from 45% in 1994 to 26% in 1999 (P<0.001). All the other isolates were less sensitive to penicillin except for two meningococci with a penicillin MIC of 1 mg/l. The geometric mean penicillin MIC increased from 0.045 to 0.065 mg/l from 1994 to 1999. There was no significant difference in the geometric mean penicillin MICs of serogroup B and serogroup C meningococci. Penicillin susceptibility was significantly associated with a poorer outcome. Isolates from survivors of IMD had a higher geometric mean penicillin MIC (0.06 mg/l) than those from fatal cases (0.048 mg/l) (P< 0.001). This suggests that factors other than the decrease in susceptibility to penicillin observed were more relevant to outcome in IMD. All isolates were fully susceptible to ceftriaxone. Rifampicin resistance was infrequent (eight isolates in 6 years) and sporadic. A single isolate had decreased quinolone susceptibility. Despite the significant shift in susceptibility to penicillin recorded, this group of antibiotics remains a suitable treatment for IMD in Australia. 相似文献