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   15564篇
  免费   955篇
  国内免费   121篇
耳鼻咽喉   131篇
儿科学   345篇
妇产科学   885篇
基础医学   1962篇
口腔科学   324篇
临床医学   1730篇
内科学   3235篇
皮肤病学   291篇
神经病学   1146篇
特种医学   577篇
外科学   2035篇
综合类   401篇
一般理论   8篇
预防医学   816篇
眼科学   424篇
药学   1122篇
  1篇
中国医学   126篇
肿瘤学   1081篇
  2023年   72篇
  2022年   198篇
  2021年   359篇
  2020年   157篇
  2019年   310篇
  2018年   420篇
  2017年   258篇
  2016年   286篇
  2015年   446篇
  2014年   545篇
  2013年   772篇
  2012年   1120篇
  2011年   1183篇
  2010年   769篇
  2009年   633篇
  2008年   888篇
  2007年   898篇
  2006年   849篇
  2005年   810篇
  2004年   740篇
  2003年   646篇
  2002年   618篇
  2001年   560篇
  2000年   537篇
  1999年   388篇
  1998年   148篇
  1997年   137篇
  1996年   130篇
  1995年   102篇
  1994年   87篇
  1993年   75篇
  1992年   190篇
  1991年   159篇
  1990年   123篇
  1989年   135篇
  1988年   124篇
  1987年   97篇
  1986年   92篇
  1985年   80篇
  1984年   51篇
  1983年   37篇
  1982年   42篇
  1981年   32篇
  1980年   30篇
  1979年   44篇
  1978年   30篇
  1977年   31篇
  1976年   29篇
  1975年   31篇
  1973年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Overweight and obesity-related metabolic disorders in hospital employees.   总被引:1,自引:0,他引:1  
BACKGROUND: Obesity is associated with metabolic disorders and cardiovascular diseases. This study investigated the relationship between overweight and obese status and the incidence of type 2 diabetes, hypertension, hyperlipidemia and hyperuricemia. METHODS: This prospective cohort study comprised 1749 hospital employees who received baseline health check-ups in 1993. Data from the 1027 participants (832 women, 195 men; mean age, 36 +/- 7 years) who repeated check-ups in 2003 were used in the analysis. Relative risks (RRs) for development of metabolic disorders during follow-up associated with different body mass index (BMI) categories at baseline as defined by Asia-Pacific recommendations and the Department of Health in Taiwan were calculated after adjustment for covariates. RESULTS: The prevalence of overweight and obesity at baseline check-up were 17.6% and 14.5%, respectively. Obese subjects with baseline BMI >or= 25 kg/m2 had a significant multivariate-adjusted RR of 2.7 for hypertension, 14.8 for type 2 diabetes, 3.2 for hypertriglyceridemia, and 2.8 for hyperuricemia, compared to subjects with baseline BMI < 23.0 kg/m2. RR for diabetes was higher in women than in men, but RR for hypertriglyceridemia was higher in men. The risks of hypertension and hyperuricemia significantly increased for subjects with baseline BMI >or= 23 kg/m2, while RRs for type 2 diabetes increased significantly for baseline BMI >or= 24 kg/m2 and hypertriglyceridemia increased for baseline BMI >or= 25 kg/m2. The risks attributable to obesity (baseline BMI >or= 25 kg/m2) were 23.0% for hypertension, 70.8% for diabetes, 27.9% for hypertriglyceridemia, and 24.1% for hyperuricemia. CONCLUSION: This study revealed that a high prevalence of overweight and obesity was associated with significantly increased risk of development of type 2 diabetes, hypertension, hypertriglyceridemia and hyperuricemia in hospital employees, suggesting the need for programs to improve weight management.  相似文献   
93.
Neuroleptic malignant syndrome (NMS) is a potentially lethal adverse reaction to neuroleptics, which is characterized by hyperthermia, extrapyramidal symptoms, altered consciousness and autonomic dysfunction. Although NMS is most commonly induced by the high-potency neuroleptics, its development has also been associated with the use of non-neuroleptic agents that block central dopamine pathways. A 68-year-old man with generalized anxiety disorder and depressive symptoms presented at the emergency department (ED) with high fever, tremor, muscle rigidity, rhabdomyolysis and altered mental status. NMS was considered to have been caused by the recent addition and subsequent dose increase in his treatment regimen of venlafaxine, a serotonin norepinephrine reuptake inhibitor. He was successfully treated with bromocriptine, lorazepam, and fluid hydration in the ED and intensive care unit.  相似文献   
94.
When all conventional treatments for respiratory failure in patients with acute respiratory distress syndrome (ARDS) have failed, extracorporeal membrane oxygenation (ECMO) can provide a chance of survival in these desperately ill patients. A 49-year-old male patient developed septic shock and progressive ARDS after liver abscess drainage. Venovenous ECMO was given due to refractory respiratory failure on postoperative day 6. Initially, two heparin-binding hollow-fiber microporous membrane oxygenators in parallel were used in the ECMO circuit. Twenty-two oxygenators were changed in the first 22 days of ECMO support because of plasma leak in the oxygenators. Each oxygenator had an average life of 48 hours. Thereafter, a single silicone membrane oxygenator was used in the ECMO circuit, which did not require change during the remaining 596 hours of ECMO. The patient's tidal volume was only 90 mL in the nadir and less than 300 mL for 26 days during the ECMO course. The patient required ECMO support for 48 days and survived despite complications, including septic shock, ARDS, acute renal failure, drug-induced leukopenia, and multiple internal bleeding. This patient received an unusually long duration of ECMO support. However, he survived, recovered well, and was in New York Heart Association functional class I-II, with a forced expiratory volume in 1 second of 81% of the predicted level 18 months later. In conclusion, ECMO can provide a chance of survival for patients with refractory ARDS. The reversibility of lung function is possible in ARDS patients regardless of the severity of lung dysfunction at the time of treatment.  相似文献   
95.
96.
Smoking causes a dysfunction in endothelial nitric-oxide synthase (eNOS), which is ameliorated, in part, by administration of tetrahydrobiopterin (BH(4)). The exact mechanism by which the nitric oxide deficit occurs is unknown. We have previously shown that aqueous extracts of chemicals in cigarettes (CE) cause the suicide inactivation of neuronal NO synthase (nNOS) by interacting at the substrate-binding site. In the current study, we have found that CE directly inactivates eNOS by a process that is not affected by the natural substrate l-arginine and is distinct from the mechanism of inactivation of nNOS. We discovered that CE causes a time-, concentration-, and NADPH-dependent inactivation of eNOS in an in vitro system containing the purified enzyme, indicating a metabolic component to the inactivation. The CE-treated eNOS but not nNOS was nearly fully reactivated upon incubation with excess BH(4), suggesting that BH(4) depletion is a potential mechanism of inactivation. Moreover, in the presence of CE, eNOS catalyzed the oxidation of BH(4) to dihydrobiopterin and biopterin by a process attenuated by high concentrations of superoxide dismutase but not catalase. We speculate that a redox active component in CE, perhaps a quinone compound, causes oxidative uncoupling of eNOS to form superoxide, which in turn oxidizes BH(4). The discovery of a direct inactivation of eNOS by a compound(s) present in tobacco provides a basis not only for further study of the mechanisms responsible for the biological effects of tobacco but also a search for a potentially novel inactivator of eNOS.  相似文献   
97.
A 77-year-old woman was referred for Ga-67 scan to evaluate intermittent fever and chills that had lasted more than 20 days. The Ga-67 whole-body scan revealed a doughnut-shaped Ga-67 accumulation in the lower abdominal region. Combined Ga-67 and Tc-99m MDP bone scan confirmed that this activity was in the uterus, because the shape of the urinary bladder on bone scan was different from that of the Ga-67-avid lesion. Pyometra was proved during operation, and pus culture was performed.  相似文献   
98.
ObjectiveOur study compared the results of wedge‐shaped femoral shaft fracture following intramedullary (IM) nailing with or without fixation of the third fragment.MethodsWe retrospectively reviewed patients presenting with femoral shaft fracture with AO/OTA type 32‐B from 2011 to 2016. Patients were divided into two groups: closed reduction without touching the third fragment and open reduction with fixation of the third fragment. The fragment ratio, fragment length, nail size, dynamization or not, mRUST scores, union rate, and union time were compared between the two groups. Risk factors of non‐union were also investigated, including sex, age, fracture pattern, fracture location, dynamization, nail size, fragment ratio, fragment size, and postoperative fragment displacement.ResultsA total of 80 patients met inclusion criteria, 20 patients with wedge‐shaped shaft femoral fracture were managed with IM nailing and open reduction with fixation of the third fragment. Sixty patients were treated with IM nail without touching the third fragment. The union rate for the fixation and non‐fixation groups were 60.0% and 81.7%, respectively. The mean union time for the fixation group was 19 months vs 14 months for the non‐fixation group. Multi‐regression analysis showed larger nail size (odds ratio: 2.26) and fixation of the third fragment (odds ratio: 0.18) influenced fracture healing.ConclusionsFixation of the third fragment in wedge‐shaped shaft femoral fracture results in a longer union time and lower union rate. In the management of femoral fracture with a third fragment, a larger nail size is recommended and fixation should be performed in a closed manner. Fixation of the fragment may achieve better fracture reduction. However, disruption of the vasculature and surrounding structures may further result in nonunion of the fracture site.  相似文献   
99.
100.
Lin CH  Lin MS  Lin YH  Chen IM  Lin PR  Cheng CY  Tsai MC 《Pharmacology》2003,67(4):202-210
The pharmacological effects of BDPBI (7-bromo-1,4-dihydro-2-phenyl-4,4-bis(4-pyridinylmethyl)2H-isoquinolin-3-one dihydrochloride) were tested on isolated endothelium-containing or denuded aorta of the guinea pig. BDPBI with the formula C(27)H(24)BrCl(2)N(3)O was synthesized starting with 3-isochromanone. In the endothelium-containing preparations of the aortic rings, phenylephrine (PHE; 10 micromol/l) elicited contracture and acetylcholine (ACh; 10 micromol/l) or BDPBI (0.01-10 micromol/l) elicited relaxation effects on the PHE-precontracted preparations. The BDPBI-elicited effect on the PHE-precontracted aortic rings was not altered in the presence of adrenergic blockers (propranolol or yohimbine; 1 micromol/l) or pretreated preparations with aspirin, indomethacin (10 micromol/l) or L-NAME (1 mmol/l). However, the relaxation effects of BDPBI were blocked if the preparations were pretreated with diphenhydramine (10 micromol/l) or chloropheniramine maleate (10 micromol/l). In contrast to lower concentrations of atropine (1 micromol/l), higher concentrations of atropine (30 micromol/l) did block the effects of BDPBI on the PHE-precontracted aortic rings. HTMT dimaleate (0.01-10 micromol/l), a histamine H(1) receptor agonist, also elicited relaxation effects on the PHE-precontracted preparation, and the effects were blocked if the preparations were pretreated with diphenhydramine or chloropheniramine maleate. On isolated denuded aorta of the guinea pig, BDPBI did not elicit relaxation effects on the PHE-precontracted aortic rings. These results demonstrated that the vasorelaxation effect of BDPBI on PHE-precontracted aortic rings is partly dependent on the activation of a histaminergic receptor from the vascular endothelium. We suggested that BDPBI would be an effective vasorelaxant for cardiovascular systems.  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