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   391篇
  免费   23篇
  国内免费   34篇
儿科学   18篇
妇产科学   1篇
基础医学   24篇
口腔科学   3篇
临床医学   73篇
内科学   63篇
皮肤病学   3篇
神经病学   4篇
特种医学   117篇
外科学   15篇
综合类   36篇
预防医学   8篇
眼科学   3篇
药学   69篇
肿瘤学   11篇
  2022年   1篇
  2021年   4篇
  2020年   1篇
  2018年   11篇
  2017年   3篇
  2016年   3篇
  2015年   4篇
  2014年   7篇
  2013年   8篇
  2012年   9篇
  2011年   12篇
  2010年   7篇
  2009年   16篇
  2008年   9篇
  2007年   33篇
  2006年   7篇
  2005年   5篇
  2004年   10篇
  2003年   8篇
  2002年   15篇
  2001年   15篇
  2000年   14篇
  1999年   15篇
  1998年   27篇
  1997年   21篇
  1996年   15篇
  1995年   20篇
  1994年   26篇
  1993年   13篇
  1992年   4篇
  1991年   4篇
  1990年   5篇
  1989年   13篇
  1988年   12篇
  1987年   8篇
  1986年   9篇
  1985年   11篇
  1984年   8篇
  1983年   2篇
  1982年   8篇
  1981年   7篇
  1980年   8篇
  1979年   1篇
  1978年   3篇
  1977年   1篇
  1976年   4篇
  1975年   1篇
排序方式: 共有448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.
Background: In hemodialysis, hypertension is treated by removing excess fluid and antihypertensive therapy. Commonly, the antihypertensives used to treat hypertension in earlier stages of kidney disease are continued as the patient progresses into end-stage renal disease and begins dialysis, without much evidence for benefit. Methods: This study is a single center, retrospective chart review that included hemodialysis patients admitted for congestive heart failure (CHF), fluid overload, or pulmonary edema as determined by ICD-9 code (428.x, 276.6, 518.4, 506.1). The primary objective was to determine if the number or class of antihypertensives used in the chronic hemodialysis population increased the number of readmissions related to CHF, fluid overload, or pulmonary edema. Patients were separated into two groups based on total number of antihypertensive medications, less than or equal to 2 medications for group 1 and greater than two medications for group 2. The primary endpoint was 30-day readmission for CHF, fluid overload, or pulmonary edema. Results: For the study period, 85 individual patient charts met inclusion criteria. Group 1 (n?=?44) experienced seven readmissions (16%) and group 2 (n?=?41) experienced eight readmissions (18%) (p?=?0.663). The most common antihypertensives at discharge were ACE inhibitors for group 1 (45%) and dihydropyridine calcium channel blockers for group 2 (66%). No difference in systolic blood pressures before, during and after hemodialysis was found between groups. Conclusions: Antihypertensive medications continue to play an important role in the hemodialysis population. This study suggests that drug class and quantity of antihypertensives do not alter readmission rate in the setting of fluid overload.  相似文献   
10.
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