全文获取类型
收费全文 | 3557篇 |
免费 | 346篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 99篇 |
妇产科学 | 67篇 |
基础医学 | 580篇 |
口腔科学 | 61篇 |
临床医学 | 484篇 |
内科学 | 787篇 |
皮肤病学 | 48篇 |
神经病学 | 193篇 |
特种医学 | 217篇 |
外科学 | 444篇 |
综合类 | 72篇 |
一般理论 | 35篇 |
预防医学 | 356篇 |
眼科学 | 53篇 |
药学 | 241篇 |
2篇 | |
中国医学 | 1篇 |
肿瘤学 | 115篇 |
出版年
2022年 | 27篇 |
2021年 | 44篇 |
2020年 | 30篇 |
2019年 | 54篇 |
2018年 | 65篇 |
2017年 | 60篇 |
2016年 | 52篇 |
2015年 | 73篇 |
2014年 | 83篇 |
2013年 | 136篇 |
2012年 | 139篇 |
2011年 | 126篇 |
2010年 | 81篇 |
2009年 | 100篇 |
2008年 | 124篇 |
2007年 | 135篇 |
2006年 | 122篇 |
2005年 | 109篇 |
2004年 | 104篇 |
2003年 | 90篇 |
2002年 | 118篇 |
2001年 | 105篇 |
2000年 | 114篇 |
1999年 | 105篇 |
1998年 | 64篇 |
1997年 | 64篇 |
1996年 | 54篇 |
1995年 | 46篇 |
1994年 | 47篇 |
1993年 | 39篇 |
1992年 | 100篇 |
1991年 | 108篇 |
1990年 | 97篇 |
1989年 | 100篇 |
1988年 | 82篇 |
1987年 | 78篇 |
1986年 | 70篇 |
1985年 | 70篇 |
1984年 | 57篇 |
1983年 | 58篇 |
1982年 | 34篇 |
1981年 | 29篇 |
1980年 | 26篇 |
1979年 | 48篇 |
1978年 | 48篇 |
1977年 | 28篇 |
1976年 | 30篇 |
1974年 | 31篇 |
1973年 | 32篇 |
1972年 | 27篇 |
排序方式: 共有3907条查询结果,搜索用时 13 毫秒
41.
We describe identical twin sisters born to nonconsanguineous, healthy parents. Both twins had situs viscerum inversus and developed hypertrophic cardiomyopathy in adulthood. 相似文献
42.
Effect of errors in the sequence of optical densities from the Roche AMPLICOR HIV-1 MONITOR assay on the validity of assay results
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)
Specifications for the AMPLICOR HIV-1 MONITOR kit indicate that the results are invalid if the optical densities (ODs) from the PCR-amplified sample that are between 0.1 and 2.3 units are out of sequence. However, among 11,904 assays, results were biased only when ODs of 0.2 to 2.0 units were out of sequence, reducing the rate of invalid results from 3.2 to 0.59%. 相似文献
43.
44.
Summary The use ofToxorhynchites brevipalpis as a system for the propagation and isolation of bluetongue virus (BTV) was investigated.BTV was found to multiply inT. brevipalpis after infection by intrathoracic inoculation. Virus concentrations of up to 6.9 log10 TCID50 per mosquito were found within 7 days of infection and were maintained for at least 6 days. Virus could be detected by an indirect fluorescent antibody test applied to head and thorax tissue smears. These results are comparable to those obtained after inoculation ofCulicoides variipennis with the same virus.Comparison ofT. brevipalpis and baby hamster kidney (BHK) cells as systems for isolation of BTV showed that there was little difference in sensitivity between the two systems for the stock BTV used. Field samples were not available for test. It was concluded that the use ofT. brevipalpis as an isolation system for BTV would have no apparent advantage if BHK cells were available.With 1 Figure 相似文献
45.
Analysis of the roles of bluetongue virus outer capsid proteins VP2 and VP5 in determination of virus serotype 总被引:5,自引:0,他引:5
P.P.C. Mertens S. Pedley J. Cowley J.N. Burroughs A.H. Corteyn M.H. Jeggo D.M. Jennings B.M. Gorman 《Virology》1989,170(2):561-565
Analyses of reassortant and parental strains of BTV serotypes 3 and 10, in serum neutralization tests, confirmed the major role of outer capsid protein VP2 in determination of virus serotype and its involvement in serum neutralization. However, a reassortant BTV strain (R70), containing protein VP5 derived from BTV 3 and VP2 derived from BTV 10, cross-neutralized with both parental virus strains (BTV 3 and BTV 10). It is concluded that VP5 also plays some part in serotype determination of these virus isolates, as analyzed by serum-neutralization, but its role may be less significant than that of VP2. 相似文献
46.
J. Richard Jennings Maurits W. VAN DER Molen Riek J.M. Somsen Cynthia Terezis 《Psychophysiology》1990,27(4):385-395
The influence of inducing motor responses of low and high force at different times in the cardiac cycle was examined. A handgrip response was used which allowed the separation of response initiation from response completion. Based on earlier work, we expected initiation, rather than completion, to initiate poststimulus cardiac acceleration. We also thought that preparation for a high force response might alter preparatory changes of interbeat interval differently from preparation for a low force response. Fifteen college-aged male subjects performed a warned reaction time task in which a visual stimulus signalled a handgrip requiring either a high or a low force to close. NoGo trials in which an inhibit signal was presented occurred on 12% of the trials. Stimuli occurred either on the R-wave of the electrocardiogram or 300 ms later. Reaction speed was varied in different trial blocks by rewarding response times of 200 ms (+/- 50 ms), 300 ms, or 400 ms. Results based on the timing of response initiation were essentially identical to those based on the timing of response completion. High force relative to low force was associated with both earlier response initiation and earlier cardiac acceleration. Force did not alter preparatory cardiac deceleration. Force and response speed did, however, alter the level of heart rate after response occurrence. Thus, response initiation (or an earlier response process) appears to induce a cardiac acceleration whose level is influenced by the speed and force of the motor response. 相似文献
47.
Timothy A. Jennings MD Ng Bernard MD Ann Boguniewicz MD Muzaffar Khan MD Donald Rice MD James Figge MD 《Endocrine pathology》1998,9(4):353-361
Hemorrhagic adrenal pseudocysts are uncommon nonneoplastic lesions that have been reported as secondary to intraparenchymal
hemorrhage or alternatively related to endothelial (vascular) cysts. Ultrastructural and immunohistochemical evidence in support
of the latter has been presented, but the exact nature of hemorrhagic adrenal pseudocysts remains poorly defined. We evaluated
six surgical specimens of hemorrhagic adrenal pseudocysts using immunohistochemical staining for CD31 and CD34, as well as
conventional histochemistry. All six cases had hemorrhagic contents within a wall of variable thickness possessing focal areas
of linear, disrupted elastin, and smooth muscle. Three cases demonstrated extensive thrombosis with organization, including
papillary endothelial hyperplasia, simulating angiosarcoma. In these cases, CD31 and CD34 staining decorated areas of papillary
endothelial hyperplasia as well as foci of the internal cyst lining, whereas the other cases were negative for both antibodies.
Of interest is the history of FNA prior to surgical resection in three cases of hemorrhagic adrenal pseudocysts, two of which
showed papillary endothelial hyperplasia. The presence of papillary endothelial hyperplasia and our immunohistochemical findings
support, the conclusion that adrenal pseudocysts are posthemorrhagic and derive from vascular disruption. Furthermore, FNA
or other interventional studies may be associated with papillary endothelial hyperplasia in hemorrhagic adrenal pseudocysts. 相似文献
48.
Overflow of catecholamine neurotransmitters to the circulation: source, fate, and functions 总被引:27,自引:0,他引:27
M Esler G Jennings G Lambert I Meredith M Horne G Eisenhofer 《Physiological reviews》1990,70(4):963-985
49.
Publication Guidelines for Heart Rate Studies in Man 总被引:1,自引:0,他引:1
J. Richard Jennings W. Keith Bberg J. Stanford Hutcheson Paul Obrist Stephen Porges Graham Turpin 《Psychophysiology》1981,18(3):226-231
Publication guidelines are provided for the collection, quantification, and analysis of heart rate data. 相似文献
50.
L. J. Jennings G. M. Salido M. -J. Pozo J. S. Davison K. A. Sharkey R. W. Lea J. Singh 《Inflammation research》1995,44(10):447-453
We have investigated the effects of histamine on motility of the gallbladder and characterized the receptor types involved. Histamine and the histamine H1-receptor agonist, 2-thiazolylethylamine (2-TEA) contracted the isolated guinea-pig gallbladder strip in a dose dependent manner. The contractile response to histamine was shifted to the right by the H1-receptor antagonist, mepyramine. In pre-contracted gallbladder strips, the H2-receptor agonist dimaprit reduced the tension generated in a dose dependent fashion. The histamine H2-receptor antagonist, ranitidine shifted the histamine concentration effect curve to the left and attenuated the dose dependent relaxations elicited at high concentrations. The histamine H3-receptor agonist, (R)--methylhistamine (RMHA) elicited dose dependent contraction of the tissue which was significantly inhibited in the presence of mepyramine. The effects of electrical field stimulation (EFS) on the strips were not significantly altered by the presence of RMHA (10–10–10–7 M) indicating little pre-synaptic H3 activity in this tissue. Histamine immunoreactivity (IR) was detected in gallbladder whole mount preparations of the mucosa and the muscularis/serosa. The histamine IR appeared cell bound in cells of varying morphological characteristics but no IR was detected in nerve fibres or cell bodies (ganglia). Alcian blue staining was consistent with the distribution of histamine IR cells as mast cells. The results indicate that histamine is distributed in the guinea-pig gallbladder and it can regulate contractile activity via activation of H1 and H2 but not H3 receptors. 相似文献