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   539篇
  免费   33篇
  国内免费   35篇
耳鼻咽喉   1篇
儿科学   20篇
妇产科学   20篇
基础医学   58篇
口腔科学   11篇
临床医学   92篇
内科学   83篇
皮肤病学   4篇
神经病学   31篇
特种医学   121篇
外科学   23篇
综合类   36篇
预防医学   27篇
眼科学   14篇
药学   44篇
肿瘤学   22篇
  2021年   5篇
  2020年   5篇
  2019年   5篇
  2018年   8篇
  2017年   5篇
  2015年   5篇
  2014年   6篇
  2013年   23篇
  2012年   18篇
  2011年   16篇
  2010年   12篇
  2009年   22篇
  2008年   20篇
  2007年   31篇
  2006年   9篇
  2005年   12篇
  2004年   20篇
  2003年   17篇
  2002年   15篇
  2001年   21篇
  2000年   24篇
  1999年   11篇
  1998年   27篇
  1997年   22篇
  1996年   18篇
  1995年   18篇
  1994年   23篇
  1993年   17篇
  1992年   4篇
  1991年   5篇
  1990年   10篇
  1989年   18篇
  1988年   13篇
  1987年   11篇
  1986年   14篇
  1985年   12篇
  1984年   14篇
  1983年   5篇
  1982年   10篇
  1981年   11篇
  1980年   10篇
  1979年   4篇
  1978年   6篇
  1976年   5篇
  1975年   2篇
  1947年   2篇
  1927年   2篇
  1923年   4篇
  1922年   1篇
  1913年   1篇
排序方式: 共有607条查询结果,搜索用时 15 毫秒
1.
2.
The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post- ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri- implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.   相似文献   
3.
AJ Unwin  BL Smith  RL Allum  G Singer  JMR Burwell   《The Knee》1995,2(4):233-234
We performed a randomized doubled-blind study to evaluate whether there was a benefit in delay in tourniquet deflation with intra-articular administration of morphine and bupivacaine following operative arthroscopic surgery. In 34 patients the tourniquet was deflated immediately and in 38 patients the tourniquet remained inflated for 10 min following injection. The analgesic efficacy was assessed using pain scores and the amount of supplementary analgesia required. The results demonstrate no benefit in delay in tourniquet deflation.  相似文献   
4.
急性有机磷农药中毒120例的救治   总被引:1,自引:0,他引:1  
0 引言 近年来 ,我科在救治急性有机磷农药 (organophos-phorus,OP)中毒方面 ,积累了一些经验 ,现报告如下 .1 对象和方法1 .1 对象 本组 1 2 0例符合《急诊急救学》中的诊断标准 [1 ](男 2 9例 ,女 91例 ) ,年龄 1 .5~ 70岁 ,平均 2 8.6岁 .经口中毒 99例 ,经皮肤中毒 2 1例 .轻度中毒 1 5例 ,中度中毒 42例 ,重度 (含极重度 )中毒 6 3例 . 1 996年 39例 ,1 997年 43例 ,1 998年 38例 . DDV 79例 ,乐果 2 0例 ,混合性中毒 1 0例 ,水胺磷 3例 ,氧化乐果、 391 1、 1 0 5 9、对硫磷各 2例 ,敌百虫 1例 ,药名不详 1 0例 .服毒量 >2 5 …  相似文献   
5.
Upham  BL; Kang  KS; Cho  HY; Trosko  JE 《Carcinogenesis》1997,18(1):37-42
Cell to cell communication via gap junctions is essential in the maintenance of the homeostatic balance of multicellular organisms. Aberrant intercellular gap junctional communication (GJIC) has been implicated in tumor promotion, neuropathy and teratogenesis. Oxidative stress has also been implicated in similar pathologies such as cancer. We report a potential link between oxidative stress and GJIC. Hydrogen peroxide, a known tumor promoter, inhibited GJIC in WB-F344 rat liver epithelial cells with an I50 value of 200 microM. Inhibition of GJIC by H2O2 was reversible as indicated by the complete recovery of GJIC with the removal of H2O2 via a change of fresh media. Free radical scavengers, such as t-butyl alcohol, propylgallate, and Trolox, did not prevent the inhibition of GJIC by H2O2, which indicated that the effects of H2O2 on GJIC was probably not a consequence of aqueous free radical damage. The depletion of intracellular GSH reversed the inhibitory effect of H2O2 on GJIC. The treatment of glutathione- sufficient cells with H2O2 resulted in the hyperphosphorylation of connexin43, which is the basic subunit of the hexameric gap junction protein, as determined by Western blot analysis. TPA, a well-known tumor promoter, also inhibits GJIC via hyperphosphorylation of GJIC, which is a result of protein kinase-C activation. However, H2O2 also induced hyperphosphorylation in GSH-deficient cells that had normal rates of GJIC. Therefore, the mechanism of GJIC inhibition must be different from the TPA-pathway and involves GSH.   相似文献   
6.
7.
8.
Angiogenic factors stimulate mast-cell migration   总被引:18,自引:1,他引:18  
Gruber  BL; Marchese  MJ; Kew  R 《Blood》1995,86(7):2488-2493
Mast cells accumulate at sites of angiogenesis. The factor(s) that control mast-cell recruitment at these sites have yet to be defined. We sought to determine if angiogenic factors result in mast-cell chemotaxis. In this study, we observed that platelet-derived growth factor-AB (PDGF-AB), vascular endothelial cell growth factor (VEGF), and basic fibroblast growth factor (bFGF) each cause directed migration of murine mast cells at picomolar concentrations, with a typical bell- shaped dose-response curve. Another potent angiogenic factor, platelet- derived endothelial cell growth factor (PD-ECGF), appears to promote chemokinesis of mast cells, whereas tumor necrosis factor-alpha, a weak angiogenic factor, is less robust but still functions as a mast cell chemotactic factor. Epidermal growth factor (EGF), a growth factor with minimal angiogenic properties, was ineffective as a mast cell chemotactic factor. A checkerboard analysis confirmed the directional chemotactic response of PDGF-AB, VEGF, and bFGF, while indicating the chemokinetic response induced by PD-ECGF. Cross-desensitization of growth-factor-induced directed migration was observed between PDGF-AB and bFGF, and also between PDGF-AB and PD-ECGF. Tyrosine kinase- inhibitor genistein effectively dampened the chemotactic responses, whereas pertussis toxin had no effect. In summary, our findings suggest that factors known to act on endothelial cells and stimulate neovascularization may simultaneously serve to recruit mast cells to these sites. The local accumulation of mast cells is believed to facilitate new vessel formation through complex cell:cell interactions.  相似文献   
9.
Polymorphisms in TMEM106B, a gene on chromosome 7p21.3 involved in lysosomal trafficking, correlates to worse neuropathological, and clinical outcomes in frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) with TDP‐43 inclusions. In a small cohort of C9orf72 expansion carriers, we previously found an atypical, neuroglial tauopathy in cases harboring a TMEM106B rs1990622 A/A genotype. To test whether TMEM106B genotype affects the risk of developing atypical tauopathy under a recessive genotype model (presence versus absence of two major alleles: A/A vs. A/G and G/G). We characterized the atypical tauopathy neuropathologically and determined its frequency by TMEM106B rs1990622 genotypes in 90 postmortem cases with a primary diagnosis of FTLD/ALS‐TDP [mean age at death 65.5 years (±8.1), 40% female]. We investigated the effect of this new atypical tauopathy on demographics and clinical and neuropsychological metrics. We also genotyped TMEM106B in an independent series with phenotypically similar cases. Sixteen cases (16/90, 17.7 %) showed the temporal‐predominant neuro‐astroglial tauopathy, and 93.7% of them carried an A/A genotype (vs. ~35% in a population cohort). The odds ratio of FTLD/ALS‐TDP individuals with the A/A genotype showing neuro‐astroglial tauopathy was 13.9. Individuals with this tauopathy were older at onset (p = 0.01). The validation cohort had a similarly high proportion of rs1990622 A/A genotype. TDP‐43 and tau changes co‐occur in a subset of neurons. Our data add to the growing body of evidence that TMEM106B polymorphisms may modulate neurodegeneration. A distinctive medial temporal predominant, 4‐repeat, neuro‐astroglial tauopathy strongly correlates to TMEM106B A/A genotype in FTLD/ALS‐TDP cases.  相似文献   
10.
BackgroundNursing documentation is essential for facilitating the flow of information to guarantee continuity, quality and safety in care. High-quality nursing documentation is frequently lacking; the implementation of computerized decision support systems is expected to improve clinical practice and nursing documentation.AimThe present study aimed at investigate the effects of a computerized decision support system and an educational program as intervention strategies for improved nursing documentation practice on pressure ulcers and malnutrition in nursing homes.Design, setting and participantsAn intervention study with two intervention groups and one control group was used. Fifteen nursing homes in southern Norway were included. A convenience sample of electronic healthcare records from 46 units was included. Inclusion criteria were records with presence of pressure ulcers and/or malnutrition. The residents were assessed before and after an intervention of a computerized decision support system in the electronic healthcare records. Data were collected through a review of 150 records before (2007) and 141 records after the intervention (2009).MethodsThe nurses in intervention group 1 were offered educational sessions and were trained to use the computerized decision support system, which they used for eight months in 2008 and 2009. The nurses in intervention group 2 were offered the same educational program but did not use the computerized decision support system. The nurses in the control group were not subject to any intervention. The resident records were examined for the completeness and comprehensiveness of the documentation of pressure ulcers and malnutrition with three data collection forms and the data were analyzed with non-parametric statistics.ResultsThe implementation of the computerized decision support system and the educational program resulted in a more complete and comprehensive documentation of pressure ulcer- and malnutrition-related nursing assessments and nursing interventions.ConclusionThis study provides evidence that the computerized decision support system and an educational program as implementation strategies had a positive influence on nursing documentation practice.  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