首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1688篇
  免费   171篇
  国内免费   10篇
耳鼻咽喉   38篇
儿科学   55篇
妇产科学   28篇
基础医学   212篇
口腔科学   48篇
临床医学   168篇
内科学   315篇
皮肤病学   19篇
神经病学   115篇
特种医学   142篇
外科学   295篇
综合类   83篇
预防医学   180篇
眼科学   16篇
药学   83篇
肿瘤学   72篇
  2022年   12篇
  2021年   27篇
  2019年   20篇
  2018年   25篇
  2017年   17篇
  2016年   15篇
  2014年   29篇
  2013年   42篇
  2012年   53篇
  2011年   71篇
  2010年   30篇
  2009年   35篇
  2008年   64篇
  2007年   64篇
  2006年   82篇
  2005年   57篇
  2004年   45篇
  2003年   53篇
  2002年   32篇
  2001年   60篇
  2000年   65篇
  1999年   54篇
  1998年   36篇
  1997年   26篇
  1996年   34篇
  1995年   25篇
  1994年   30篇
  1993年   21篇
  1992年   43篇
  1991年   41篇
  1990年   44篇
  1989年   47篇
  1988年   58篇
  1987年   49篇
  1986年   52篇
  1985年   47篇
  1984年   27篇
  1983年   31篇
  1982年   20篇
  1981年   15篇
  1980年   26篇
  1979年   32篇
  1978年   22篇
  1977年   21篇
  1976年   13篇
  1975年   16篇
  1974年   12篇
  1973年   13篇
  1972年   14篇
  1970年   12篇
排序方式: 共有1869条查询结果,搜索用时 0 毫秒
1.
In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.  相似文献   
2.
Kim  EE; Pjura  G; Lowry  P; Verani  R; Sandler  C; Flechner  S; Kahan  B 《Radiology》1986,159(2):443-446
Serial radionuclide studies using both Tc-99m DTPA (perfusion) and I-131 hippuran (tubular function) were correlated with histologic findings in 25 patients with renal transplants. These cases included 15 cases of cyclosporin-A nephrotoxicity (CsA-NT) and ten cases of acute cellular rejection that were retrospectively selected on the basis of biopsy findings and favorable clinical response to therapy specific for each of these conditions. The serial radionuclide studies enabled the correct diagnosis in 12 of 15 cases of CsA-NT and eight of ten cases of acute rejection. Posttherapy radionuclide studies, furthermore, demonstrated improvement consistent with clinical response. In all cases, the radionuclide results were available at least 24 hours before biopsy findings. These results indicate that serial radionuclide studies evaluating interval changes in both perfusion and tubular function are of significant value in the diagnosis and follow-up of CsA-NT and acute cellular rejection in transplant recipients. This initial experience suggests a sensitivity of 80%.  相似文献   
3.
4.
An intraperitoneal injection of the preferential opiate receptor agonist (+/-) bremazocine HCl given to male rough-skinned newts acutely and dose-dependently reduced their spontaneous locomotor activity. Inversely, and contrary to the situation generally observed in other vertebrates, administration of the opiate receptor antagonist naloxone HCl dose-dependently and acutely stimulated locomotion. Given at a behaviorally active dosage, naloxone counteracted the inhibitory effect of bremazocine on locomotion. The behavioral influence of the two substances was observed using two different sampling techniques (continuous recording for 3 minutes: repeated instantaneous sampling for 60 minutes). These data are discussed in view of our current knowledge on the opiate regulation of locomotor activity in vertebrates.  相似文献   
5.
We report two brothers of Chinese origin who have an apparently unique syndrome of cleft lip/palate, profound sensorineural deafness, and a sacral lipoma. Additional findings which were not common to both were aberrant digital appendages on the heel and thigh of one boy and an anterior sacral meningocele and dislocated hip in the other. Intelligence is normal in both. Both boys suffer from functional constipation but biopsy studies showed no evidence of Hirschsprung's disease. The parents, who are normal, are not related. Inheritance is probably autosomal or X linked recessive. A possible link with the disorganisation mouse mutant is discussed.  相似文献   
6.
7.
We have determined the frequency of heterozygosity of the short arm of chromosome 17 in 20 cervical tumours using the highly polymorphic probe pYNZ22. Only 25% of the tumours were heterozygous at this locus. This is significantly lower than the level of 86% heterozygosity for this locus in the general population indicating that loss of one allele occurs in cervical cancer. Heterozygosity for a locus on the long arm of the same chromosome showed no significant difference between the tumours and the general population indicating that genetic loss was confined to the short arm of the chromosome. The analysis of premalignant lesions showed 70% of patients were heterozygous suggesting that loss of material from the short arm of chromosome 17 took place at a late stage in tumour development. This report confirms predictions made from previous karyotypic analysis and is the first indication of allele loss on the short arm of chromosome 17 in cervical cancer.  相似文献   
8.
9.
Widely reported cases of research fraud have eroded public confidence in scientific research. When funding agencies met last fall they underscored the importance of integrity in the research process and discussed steps that could be taken to promote it.  相似文献   
10.
Anti-endotoxin therapy in primate bacteremia with HA-1A and BPI.   总被引:4,自引:1,他引:3  
OBJECTIVE: The in vivo neutralizing activities of an anti-lipopolysaccharide (LPS) antibody HA-1A (Centoxin [Centocor, Malvern, PA]), a human immunoglobulin M monoclonal antibody, and of bactericidal/permeability-increasing protein (BPI), an endogenously produced human LPS-neutralizing protein, were studied in a primate model of lethal Escherichia coli bacteremia. SUMMARY BACKGROUND DATA: HA-1A has been used with variable success against LPS activity in some animal models and in a recently reported clinical trial. However, no data assessing the efficacy of this agent in subhuman primates is available. Bactericidal/permeability-increasing protein is a product of polymorphomononuclear cells (PMNs) that is stored in azurophilic granules and exhibits LPS-neutralizing activity in vitro and in some in vivo models. METHODS: Immediately after E. coli infusion and in a blinded fashion, three baboons were treated with BPI (5 mg/kg bolus infusion and 95 micrograms/kg/min infusion over 4 hr). Three animals received 3 mg/kg BW of HA-1A, whereas another three baboons received a placebo treatment. RESULTS: The BPI-treated animals demonstrated significantly (p < 0.03) lower circulating LPS-limulus amoebocyte lysate (LAL) activity compared with the control animals, but this reduction in LPS-LAL activity was not associated with improved survival. HA-1A treatment did not reduce LPS-LAL activity. However, both BPI and HA-1A treatment did attenuate the pro-inflammatory cytokine response. CONCLUSION: The current data suggests that incomplete neutralization of endotoxin activity does not alter mortality from severe bacteremia. Given the diversity of mediator production under such circumstances, a strategy of combination therapy in the form of anti-lipopolysaccharide and anticytokine treatment may be necessary to achieve optimal survival.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号