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   546篇
  免费   32篇
  国内免费   35篇
耳鼻咽喉   3篇
儿科学   23篇
妇产科学   6篇
基础医学   54篇
口腔科学   8篇
临床医学   52篇
内科学   143篇
皮肤病学   4篇
神经病学   19篇
特种医学   122篇
外科学   52篇
综合类   36篇
预防医学   25篇
眼科学   4篇
药学   39篇
肿瘤学   23篇
  2021年   4篇
  2020年   5篇
  2018年   7篇
  2017年   7篇
  2016年   7篇
  2015年   5篇
  2014年   8篇
  2013年   19篇
  2012年   25篇
  2011年   20篇
  2010年   18篇
  2009年   20篇
  2008年   23篇
  2007年   37篇
  2006年   12篇
  2005年   15篇
  2004年   19篇
  2003年   11篇
  2002年   17篇
  2001年   17篇
  2000年   20篇
  1999年   17篇
  1998年   28篇
  1997年   22篇
  1996年   18篇
  1995年   20篇
  1994年   25篇
  1993年   13篇
  1992年   8篇
  1991年   4篇
  1990年   10篇
  1989年   18篇
  1988年   17篇
  1987年   13篇
  1986年   11篇
  1985年   15篇
  1984年   12篇
  1983年   5篇
  1982年   12篇
  1981年   8篇
  1980年   10篇
  1979年   1篇
  1978年   4篇
  1977年   1篇
  1976年   4篇
  1975年   1篇
排序方式: 共有613条查询结果,搜索用时 15 毫秒
31.
Results of earlier spatial-orientation studies focusing on the sense of verticality have emphasized an intriguing paradox. Despite evidence that nearly veridical signals for gravicentric head orientation and egocentric visual stimulus orientation are available, roll-tilted subjects err in the direction of the long body axis when adjusting a visual line to vertical in darkness (Aubert effect). This has led to the suggestion that a central egocentric bias signal with fixed strength and direction acts to pull the perceived vertical to the subjects' zenith (M-model). In the present study, the subjective visual vertical (SVV) was tested in six human subjects, across the entire 360 degrees range. For comparison, body-tilt estimates from four subjects where collected in a separate series of experiments. For absolute tilts up to approximately 135 degrees, SVV responses showed a gradually increasing Aubert effect that could not be attributed to errors in perceived body tilt but was nicely in line with the M-model. At larger absolute tilts, SVV errors abruptly reversed sign, now showing a pattern concordant with errors in body-tilt estimates but incompatible with the M-model. These results suggest that, in the normal working range, the perception of external space and the perception of body posture are based on different processing of body-tilt signals. Beyond this range, both spatial-orientation tasks seem to rely mainly on a common tilt signal.  相似文献   
32.
33.
Dronedarone (Dron), without iodine, was developed as an alternative to the iodine-containing antiarrhythmic drug amiodarone (AM). AM acts, via its major metabolite desethylamiodarone, in vitro and in vivo as a thyroid hormone receptor alpha(1) (TRalpha(1)) and TRbeta(1) antagonist. Here we investigate whether Dron and/or its metabolite debutyldronedarone inhibit T(3) binding to TRalpha(1) and TRbeta(1) in vitro and whether dronedarone behaves similarly to amiodarone in vivo. In vitro, Dron had a inhibitory effect of 14% on the binding of T(3) to TRalpha(1), but not on TRbeta(1). Desethylamiodarone inhibited T(3) binding to TRalpha(1) and TRbeta(1) equally. Debutyldronedarone inhibited T(3) binding to TRalpha(1) by 77%, but to TRbeta(1) by only 25%. In vivo, AM increased plasma TSH and rT(3), and decreased T(3). Dron decreased T(4) and T(3), rT(3) did not change, and TSH fell slightly. Plasma total cholesterol was increased by AM, but remained unchanged in Dron-treated animals. TRbeta(1)-dependent liver low density lipoprotein receptor protein and type 1 deiodinase activities decreased in AM-treated, but not in Dron-treated, animals. TRalpha(1)-mediated lengthening of the QTc interval was present in both AM- and Dron-treated animals. The in vitro and in vivo findings suggest that dronedarone via its metabolite debutyldronedarone acts as a TRalpha(1)-selective inhibitor.  相似文献   
34.
1 病例报告 患者,28岁,因“停经3mo余,不规则阴道流血2mo余,于1999-06-30入院.患者1993年足月妊娠剖宫产一男婴.末次月经1999-03-12,06-14始阴道少量流血,无腹痛.04-28当地医院B超提示“不全流产”,未行清宫术....  相似文献   
35.
Ornithine carbamoyl transferase (OCT) activity and other liver function tests were studied in a total of 50 patients of clinical malaria and 15 controls. They were grouped as group I (positive for malarial parasite on peripheral blood smear, n=18), group II (negative for malarial parasite on peripheral blood smear (PBS) but responded to antimalarials, n=17) and group III (peripheral blood smear negative and did not respond to antimalarial therapy, n=15). The mean OCT levels were significantly raised in group I (6.79 ± 1.84 IU/L, p value = 0.006) and group II (5.0 ± 1.15 IU/L, p value = 0.014) as compared to controls (2.5 ± 1.13 IU/L) and returned to normal after treatment In contrast, group III had normal levels except in a case of kala azar and septicemia where OCT levels were high and increased further on treatment. Taking PBS positivity as a gold standard of diagnostic criteria, OCT had a sensitivity of 83% and specificity of 86% with a high positive predictive value of 88% as compared to ALT which had a lower sensitivity of 55% and specificity of 80%. The clinical response rate in PBS negative cases of fever having high OCT level was 83% as compared to 35% in cases with normal OCT level, making OCT a good surrogate marker of malaria. OCT levels could also be of prognostic significance as 2 cases of cerebral malaria had high OCT levels of 11.1 UAL and 10.7 IU/L, respectively.Key Words: Malaria, Ornithine carbamoyl transferase  相似文献   
36.
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   
37.
Clin. Otolaryngol. 2010, 35 , 31–38. Objective: To examine psychosocial concomitants, illness perceptions, and treatment perceptions in patients with adductor spasmodic dysphonia. Design: Prospective controlled cohort study. Setting: A tertiary care facility. Participants: Forty-nine out-patients (38 women, 11 men; average age of 52 years) with adductor spasmodic dysphonia completed a battery of reliable and validated psychometric assessment instruments. Control patients’ data were derived from scores in questionnaires by samples in the formal Manuals of the questionnaires used. Main outcome measures: Psychosocial functioning, illness perceptions, and treatment perceptions. Results: Scores on psychosocial measures were elevated in male patients especially, indicating levels of psychological morbidity significantly above those seen in the general population. Assessments of illness perceptions and treatment perceptions indicated that patients perceive that they have a very low degree of control over the disorder, and experience a high emotional impact from it. Voice Handicap Index scores illustrated substantial degrees of perceived handicap. Conclusions: Adductor spasmodic dysphonia is associated with significant negative psychosocial concomitants, coupled with low perceived control over the condition. Future research should elucidate the implications of illness perceptions and treatment perceptions for the biopsychosocial care of persons with adductor spasmodic dysphonia in order to improve self-management and enhance quality of life.  相似文献   
38.
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   
39.
Type III iodothyronine deiodinase (D3) catalyzes the inner ring deiodination (IRD) of T4 and T3 to the inactive metabolites rT3 and 3,3'-diiodothyronine (3,3'-T2), respectively. Here we describe the cloning and characterization of complementary DNA (cDNA) coding for D3 in fish (Oreochromis niloticus, tilapia). This cDNA contains 1478 nucleotides and codes for a protein of 267 amino acids, including a putative selenocysteine (Sec) residue, encoded by a TGA triplet, at position 131. The deduced amino acid sequence shows 57-67% identity with frog, chicken, and mammalian D3, 33-39% identity with frog, fish (Fundulus heteroclitus) and mammalian D2, and 30-35% identity with fish (tilapia), chicken, and mammalian D1. The 3' UTR contains a putative Sec insertion sequence (SECIS) element. Recombinant tilapia D3 (tD3) expressed in COS-1 cells and native tD3 in tilapia brain microsomes show identical catalytic activities, with a strong preference for IRD of T3 (Km approximately 20 nM). IRD of [3,5-125I]T3 by native and recombinant tD3 are equally sensitive to inhibition by substrate analogs (T3 > T4 > rT3) and inhibitors (gold thioglucose > iodoacetate > propylthiouracil). Northern analysis using a tD3 riboprobe shows high expression of a 1.6-kb messenger RNA in gill and brain, although D3 activity is much higher in brain than in gill. The characterization of tD3 cDNA provides new information about the structure-activity relationship of iodothyronine deiodinases and an important tool to study the regulation of thyroid hormone bioactivity in fish.  相似文献   
40.
Peripheral polyneuropathy is the most frequent complication of diabetic mellitus. In spite of many clinical trials of different specific interventions for diabetic polyneuropathy, intensive glycemic control remains the only effective specific therapy currently available for this troublesome complication. This systematic overview reports the status of current clinical trials in diabetic polyneuropathy with an emphasis on those interventions directed towards specific pathophysiological derangements. A discussion of clinical trials of agents directed towards relieving painful symptoms of diabetic polyneuropathy concludes this overview.  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