全文获取类型
收费全文 | 3496篇 |
免费 | 277篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 151篇 |
妇产科学 | 79篇 |
基础医学 | 432篇 |
口腔科学 | 59篇 |
临床医学 | 451篇 |
内科学 | 771篇 |
皮肤病学 | 50篇 |
神经病学 | 244篇 |
特种医学 | 305篇 |
外科学 | 379篇 |
综合类 | 50篇 |
一般理论 | 2篇 |
预防医学 | 345篇 |
眼科学 | 23篇 |
药学 | 288篇 |
中国医学 | 2篇 |
肿瘤学 | 129篇 |
出版年
2023年 | 16篇 |
2022年 | 14篇 |
2021年 | 40篇 |
2020年 | 30篇 |
2019年 | 33篇 |
2018年 | 63篇 |
2017年 | 39篇 |
2016年 | 46篇 |
2015年 | 67篇 |
2014年 | 81篇 |
2013年 | 93篇 |
2012年 | 155篇 |
2011年 | 116篇 |
2010年 | 84篇 |
2009年 | 84篇 |
2008年 | 128篇 |
2007年 | 142篇 |
2006年 | 153篇 |
2005年 | 113篇 |
2004年 | 123篇 |
2003年 | 131篇 |
2002年 | 118篇 |
2001年 | 103篇 |
2000年 | 114篇 |
1999年 | 108篇 |
1998年 | 81篇 |
1997年 | 107篇 |
1996年 | 70篇 |
1995年 | 68篇 |
1994年 | 77篇 |
1993年 | 80篇 |
1992年 | 87篇 |
1991年 | 74篇 |
1990年 | 77篇 |
1989年 | 88篇 |
1988年 | 89篇 |
1987年 | 69篇 |
1986年 | 80篇 |
1985年 | 67篇 |
1984年 | 47篇 |
1983年 | 50篇 |
1982年 | 36篇 |
1981年 | 38篇 |
1980年 | 41篇 |
1979年 | 32篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 26篇 |
1975年 | 30篇 |
1974年 | 13篇 |
排序方式: 共有3778条查询结果,搜索用时 0 毫秒
31.
Social conflict in mice is associated with at least two forms of analgesia. A long-lasting opioid reaction is evident in intruder mice exposed to prolonged attack, whilst an acute non-opioid analgesia is seen in response to either defeat experience per se or the territorial scent-marking of an aggressive conspecific. Recent work from this laboratory has suggested that the non-opioid analgesic reaction to defeat experience may be mediated via benzodiazepine receptor mechanisms. The present studies were designed to further test this tentative hypothesis. Results confirmed that defeat analgesia is dose-dependently blocked by Ro15-1788 (20-40 mg/kg) and diazepam (2-4 mg/kg), and also indicated partial antagonism of the reaction by CGS8216 (2.5 mg/kg). The partial agonists CGS9896 (2.5-20 mg/kg) and ZK91296 (2.5-20 mg/kg) were ineffective in blocking the reaction, a finding also obtained with the full agonist ZK93423 (0.05-10 mg/kg). However, the antagonist/weak inverse agonist ZK93426 was found to possess significant intrinsic analgesic activity (10 mg/kg) and to enhance defeat analgesia (5-10 mg/kg). Although several interpretative frameworks for the current pharmacological profile are considered, it is concluded that full clarification of the substrates of defeat analgesia must await further investigations. 相似文献
32.
33.
COMT and DRD3 polymorphisms, environmental exposures, and personality traits related to common mental disorders 总被引:3,自引:0,他引:3
Henderson AS Korten AE Jorm AF Jacomb PA Christensen H Rodgers B Tan X Easteal S 《American journal of medical genetics》2000,96(1):102-107
In a community sample of 2,327 Caucasians, we tested the hypotheses that polymorphisms in the COMT and DRD3 genes are associated with personality traits conferring vulnerability to anxiety, depression, or alcohol misuse, or with current symptoms of these; and that the association is stronger in persons who also have been exposed to stressor experiences. To conserve resources and to allow replication, the genetic analysis was undertaken in two stages. For the COMT polymorphism, no statistically significant associations were found in the first sample of 862 persons. The remainder of the sample was therefore not analysed for that gene. For the DRD3 polymorphism, those in the first sample with at least one of the Ser(9) alleles had significantly higher scores in neuroticism (p=0.006) and behavioral inhibition (p=0.003). There was a trend, failing to meet the 1% significance criterion, for those with this genotype also to have higher depression and anxiety. The groups did not differ in alcohol use. In persons with the Ser(9) allele who were also exposed to stressors, there was a higher level of depression at the 5% level; and the depression level was higher in homozygotes. But when the remainder of the sample (1,465) was analysed, none of the associations reached statistical significance. We conclude that neither the COMT nor DRD3 polymorphisms are associated with anxiety, depression, or alcohol abuse. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:102-107, 2000 Copyright 2000 Wiley-Liss, Inc. 相似文献
34.
Duffy LK Scofield E Rodgers T Patton M Bowyer RT 《Comparative biochemistry and physiology. Part C, Pharmacology, toxicology & endocrinology》1999,124(2):181-186
In subsistence fish; northern pike (Esox lucius), burbot (Lota lota), whitefish (Coregonus nelsoni), grayling (Thymallus arcticus) and sheefish (Stenodus lencichthys), we determined the Hsp 60 and Hsp 70 levels in 31 samples from adult fish gills. A dot-blot analysis using antibodies to either Hsp 70 or Hsp 60 showed the average Hsp 70 concentration was 9.1 microg/mg protein, while the average Hsp 60 concentration was 147.4 microg/mg protein. Mercury levels in muscle tissue in these fish averaged 0.382 ppm. Using a subset of samples (n = 24), we determined that the major component in the muscle of Alaskan subsistence fish was methyl mercury. No correlation was observed between Hsp 60 or Hsp 70 expression in gill tissue and mercury concentrations in muscle tissue. Hsp 60 and Hsp 70 protein levels in the gills were correlated. 相似文献
35.
Griffin JF Spittle E Rodgers CR Liggett S Cooper M Bakker D Bannantine JP 《Clinical and diagnostic laboratory immunology》2005,12(12):1401-1409
This study was designed to develop a customized enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of Johne's disease (JD) in farmed deer. Two antigens were selected on the basis of their superior diagnostic readouts: denatured purified protein derivative (PPDj) and undenatured protoplasmic antigen (PpAg). ELISA development was based on the antigen reactivity of the immunoglobulin G1 (IgG1) isotype, which is a highly specific marker for mycobacterial disease seroreactivity in deer. Sensitivity estimates and test parameters were established using 102 Mycobacterium paratuberculosis-infected animals from more than 10 deer herds, and specificity estimates were determined using 508 uninfected animals from 5 known disease-free herds. A receiver-operated characteristic analysis determined that at a cut point of 50 ELISA units, there was a specificity of 99.5% and sensitivities of 84.0% with PPDj antigen, 88.0% with PpAg, and 91.0% when the antigens were used serially in a composite test. Estimated sensitivity was further improved using recombinant protein antigens unique for M. paratuberculosis, which identified infected animals that were unreactive to PPDj or PpAg. While 80% of animals that were seropositive in the IgG1 ELISA had detectable histopathology, the assay could also detect animals with subclinical disease. The test was significantly less sensitive (75%) for animals that were culture positive for M. paratuberculosis but with no detectable pathology than for those with pathological evidence of JD (>90%). When the IgG1 ELISA was used annually over a 4-year period in a deer herd with high levels of clinical JD, it eliminated clinical disease, increased production levels, and reduced JD-related mortality. 相似文献
36.
Rodgers KE; Girgis W; St Amand K; Campeau J; diZerega GS 《Human reproduction (Oxford, England)》1998,13(9):2443-2451
Adhesion formation is a major source of postoperative morbidity and
mortality. In this study, the ability of a variety of lazaroid formulations
[the antioxidant 21-aminosteroid PNU74006F (tirilazad) and the
non-steroidal 2-methylaminochroman derivative PNU83,836E] to reduce i.p.
adhesion formation in three rabbit models was examined. In initial studies,
PNU83836E was administered via Alzet miniosmotic pump to the site of
injury. In the sidewall and double uterine horn models, PNU83,836E was
administered via Alzet miniosmotic pump for the entire postoperative
interval. In the sidewall model, there was a dose- dependent reduction in
the area of the sidewall injury that was involved in adhesions. In the
double uterine horn model, PNU83,836E was administered via Alzet
miniosmotic pump to the area of injury for 1, 2, 3 or 7 days.
Administration for as little as 24 h after surgery significantly reduced
the extent of adhesion formation and the reduction was increased if it was
administered for longer. Further studies were conducted in which various
lazaroid formulations were administered as a bolus at the end of surgery.
In both the sidewall and double uterine horn models, administration of
either PNU83,386E (in citrate buffer) or PNU74006F (in cyclodextrin or
lipid emulsion vehicles) at the end of surgery reduced adhesion formation.
Administration of a bolus of PNU74006F 10 min prior to initiation of
surgery with or without additional treatment at the end of surgery further
increased its efficacy in the reduction of adhesion formation.
Administration of a minimum of 1.5 mg before and after surgery (3 mg total)
was required for maximal efficacy. These studies demonstrate that pre- and
postoperative administration of either a steroidal (PNU74006F) or
non-steroidal (PNU83,836E) lazaroid intraperitoneally reduced the formation
and reformation of postoperative adhesions in three animal models.
相似文献
37.
It has recently been proposed that a stress-activated, endogenous analgesia mechanism would be adaptive in situations in which pain perception might otherwise disrupt effective behavioural performance. In a semi-natural test situation, the current study examined two predictions arising from this hypothesis: (1) in a manner analogous to other stressors, agonistic experience should produce analgesia and, if naloxone-sensitive opioid mechanisms are implicated, then (2) pretreatment with naloxone should block the development of this response and alter the displayed behaviour patterns. Neither prediction was substantiated by the data. Experience of an agonistic encounter failed to produce analgesia in either resident or intruder animals. Furthermore, naloxone hydrochloride (1-25 mg/kg) was also without effect on patterns of offense or defense. Data are discussed in relation to the critical nature of the stimulus factors involved in the activation of endogenous analgesic mechanisms and the postulated involvement of such mechanisms in biologically-adaptive behaviours. 相似文献
38.
Detection of virus particles by electron microscopy with polyacrylamide hydrogel. 总被引:6,自引:0,他引:6 下载免费PDF全文
The use of lyphogel to concentrate the number of virus particles in specimens for electron microscopic examination was studied in parallel with ultracentrifugation. One hundred faecal and urine samples were compared. Both methods had a similar sensitivity. Lyphogel was economical, simple, and rapid in use; in contrast to ultracentrifugation, it required relatively little material. The procedure could be done within a safety cabinet, and virus particles were morphologically undamaged by the process. 相似文献
39.
An 11-year-old girl with Opitz (BBBG) syndrome presented with a bleeding disorder. Studies showed an immune-mediated qualitative platelet dysfunction in the absence of thrombocytopenia. This is the first report of hemostatic dysfunction in a patient with the Opitz (BBBG) syndrome. This report considers the possible relationship of the platelet dysfunction to the Opitz (BBBG) syndrome and its treatment. 相似文献
40.
Jonathan T. Sims Venkatesh Krishnan Ching-Yun Chang Sarah M. Engle Giacomo Casalini George H. Rodgers Nicoletta Bivi Brian J. Nickoloff Robert J. Konrad Stephanie de Bono Richard E. Higgs Robert J. Benschop Silvia Ottaviani Anabela Cardoso Ajay Nirula Mario Corbellino Justin Stebbing 《The Journal of allergy and clinical immunology》2021,147(1):107-111