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   16041篇
  免费   1020篇
  国内免费   42篇
耳鼻咽喉   330篇
儿科学   435篇
妇产科学   233篇
基础医学   2130篇
口腔科学   414篇
临床医学   1313篇
内科学   3303篇
皮肤病学   353篇
神经病学   1309篇
特种医学   1050篇
外国民族医学   10篇
外科学   2506篇
综合类   133篇
一般理论   2篇
预防医学   1078篇
眼科学   291篇
药学   1063篇
中国医学   27篇
肿瘤学   1123篇
  2021年   239篇
  2020年   141篇
  2019年   193篇
  2018年   255篇
  2017年   215篇
  2016年   280篇
  2015年   303篇
  2014年   359篇
  2013年   456篇
  2012年   712篇
  2011年   727篇
  2010年   397篇
  2009年   421篇
  2008年   711篇
  2007年   691篇
  2006年   708篇
  2005年   730篇
  2004年   670篇
  2003年   661篇
  2002年   639篇
  2001年   613篇
  2000年   603篇
  1999年   526篇
  1998年   225篇
  1997年   184篇
  1996年   176篇
  1995年   144篇
  1994年   135篇
  1993年   137篇
  1992年   332篇
  1991年   303篇
  1990年   327篇
  1989年   309篇
  1988年   274篇
  1987年   256篇
  1986年   237篇
  1985年   232篇
  1984年   195篇
  1983年   163篇
  1982年   114篇
  1981年   97篇
  1979年   156篇
  1978年   118篇
  1977年   97篇
  1976年   90篇
  1975年   110篇
  1974年   104篇
  1973年   100篇
  1970年   96篇
  1969年   94篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Body packing is a well recognized method of drug trafficking by smuggling drug containers in the gastrointestinal tract. Medical professionals might get involved with body packers after presentation by law enforcement or in case of medical emergencies such as drug overdose or mechanical intestinal obstruction due to the containers within the gastrointestinal tract. Besides the medical aspects in treating these patients, physicians must be aware of all the different legal specifics in dealing with body packers. In case of medical emergencies, drug traffickers have the legal status of regular patients with respect to professional medical discretion. The question remains of what physicians should do with the drugs after surgical removal? Even though the body packer remains the legal owner of the drugs, physicians may not return the drugs, since that constitutes the criminal offence of dealing in narcotics. Returning the drugs to law enforcement authorities is also prohibited because of professional medical discretion. The only way out of this predicament is for physicians to destroy the drugs under the observation of witnesses.  相似文献   
52.
Statins, inhibitors of the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase, are well-established agents to lower cholesterol levels and prevent cardiovascular morbidity. Independent of their lipid-lowering properties, statins have been shown to exert pleiotropic immunomodulatory effects in various animal models of human autoimmune disease. In experimental autoimmune encephalomyelitis, a murine model for multiple sclerosis, statins prevented disease onset and even reversed paralysis when treatment was initiated after experimental autoimmune encephalomyelitis was fully established. Furthermore, well-tolerated oral statins were recently shown to exert synergistic benefit in experimental autoimmune encephalomyelitis in combination with existing agents for multiple sclerosis therapy. Based primarily on these encouraging results, statins are now being tested in clinical trials as a mono-therapy for multiple sclerosis, as well as in combination with approved disease-modifying therapies.  相似文献   
53.
Alterations of blood flow contribute to major clinical complications in invasive infections such as sepsis and bacterial meningitis. As a unique feature streptococci -- in particular, Streptococcus pneumoniae, the most frequent pathogen in bacterial meningitis -- release hydrogen peroxide (H(2)O(2)) because of the absence of functional catalase. In a 6 h rat model of experimental meningitis, we studied the impact of bacterial H(2)O(2) production on regional cerebral blood flow (rCBF) and intracranial pressure (ICP). Compared to wild-type D39 pneumococci, the increase of rCBF was diminished in meningitis induced by the H(2)O(2) defective SpxB(-) mutant (maximum increase, 135% +/- 17% versus 217% +/- 23% of the individual baseline; P<0.01) or after treatment of D39-induced meningitis with H(2)O(2)-degrading catalase or with tetraethylammonium (TEA), a blocker of calcium-sensitive potassium channels, which mediate H(2)O(2)-induced vasodilation. Catalase did not significantly reduce the remaining rCBF increase caused by SpxB(-), supporting the predominant role of bacterial H(2)O(2). We conclude that in addition to host-sided mediators, bacterial-derived H(2)O(2) acts as a potent vasodilator, which accounts for a certain proportion of the early cerebral hyperperfusion in pneumococcal meningitis.  相似文献   
54.
55.
We present an adenoid cystic carcinoma of the base of tongue in a 48-year-old male with a restricted chromosomal alteration by cytogenetic and spectral karyotypic analysis (SKY). SKY and G-banding analyses identified the t(6;14)(q25;q13) as the sole structural aberration in all metaphases analyzed. This finding supports a critical role for this event in the development of this tumor. The implications of chromosome 6q translocation in this case and in previously reported adenoid cystic carcinomas are highlighted and discussed.  相似文献   
56.
57.
OBJECTIVE  Increased plasma concentrations of GH and increased GH responses to provocative stimuli are reported in patients with poorly controlled type I diabetes and are suggested to be related to complications. Our aim was to investigate GH concentrations in moderately controlled patients.
PATIENTS AND MEASUREMENTS  We have investigated IGF-I concentrations and fasting GH concentrations and the response to 1 μg/kg body weight GH-releasing hormone (GHRH) intravenously and/or to 150 μg clonidine intravenously in 77 moderately controlled patients with type I diabetes and in 46 healthy controls.
RESULTS  Median HbA1c in the patients was 8.5% (upper level of normal 6.3%). Fasting GH and GH concentrations after the administration of GHRH were not significantly different in patients with type I diabetes compared with normal controls. Fasting and stimulated GH concentrations after the administration of clonidine were significantly higher in the patients, but this could be explained by their lower age and body mass index compared with controls. In controls but not in patients there was a negative correlation between GH and glucose concentrations. IGF-I was significantly lower in patients with diabetes than in controls, even after correction for age, body mass index and sex.
CONCLUSIONS  Patients with moderately controlled type I diabetes mellitus have normal baseline and stimulated GH concentrations after the administration of GHRH or clonidine compared with healthy controls, when corrected for age, body mass index and sex. However, these 'normal' GH concentrations must be considered inappropriately high in view of the hyperglycaemia in these patients. The low plasma IGF-I concentrations might be responsible for the GH over-production.  相似文献   
58.
Summary The load axis of the curved proximal femur lies not inside but outside the bone. Therefore, high bending forces are acting, the medial cortex absorbing pressure and the lateral cortex absorbs tension. In a transverse fracture, a laterally applied plate will absorb the tensile stresses and the medial cortex, the pressure forces. When the medial buttress due to a bony defect is missing, the laterally applied plate is subjected to cyclic bending and will undergo fatigue fracture. This dilemma is compensated by a wave plate with bone graft: the compression forces are redirected to the lateral cortex, and the plate is again subjected to tension. Furthermore, since the plate stands away from the bone, it does not disturb the blood supply at the fracture site and thus bone healing.  相似文献   
59.
Between 1974 and 1984, 173 patients were treated for squamous cell carcinoma of the tongue base. Fifty-four patients had T1 or T2 primaries, while 115 patients had T3 or T4 tumors (4 were not staged). Lymph node metastasis was present in 120 patients. Early primary tumors treated with surgery or radiotherapy had a control rate of 83% (5 of 6 tumors) and 89% (40 of 45 tumors), respectively. For advanced primary tumors, definitive radiotherapy produced a local control rate of 55% (42 of 76 tumors), compared with 79% (23 of 29 tumors) for surgery and postoperative radiotherapy. If primary control was obtained, the regional failure rate was less than 10%. Tumor growth patterns were predictive of the response to radiotherapy. The primary control rate at 2 years for 21 patients with exophytic tumors was 84% as opposed to 58% for 62 patients with ulcerative-infiltrative tumors (p = 0.04). Radiotherapy is effective for early stage or exophytic tumors, whereas for advanced or deeply invasive tumors combined therapy enhances local control.  相似文献   
60.
The lack of specific agonists and antagonists has, until recently, precluded investigation of a role for dopamine receptors in the control of intraocular pressure. In the present study, we have examined the effects of fenoldopam, a novel selective dopamine1 (DA1) receptor agonist, on intraocular pressure, in eight healthy human volunteers. Fenoldopam, infused intravenously at 0.5 micrograms kg-1 min-1, increased intraocular pressure from 14.6 +/- 0.9 to 17.6 +/- 1.4 mmHg (P less than 0.05) while a control saline infusion had no effect. Pupil diameter and blood pressure did not change. In the same subjects, i.v. norepinephrine or angiotensin II both increased intraocular pressure--from 13.8 +/- 1.4- to 17.6 +/- 1.4 mmHg and from 13.4 +/- 1.3- to 17.5 +/- 1.7 mmHg respectively (P less than 0.05), and mean arterial pressure by about 20 mmHg. These data suggest that: (1) DA1 receptor activation can modulate intraocular pressure; (2) the intraocular pressure effects of the DA1 receptor agonist, fenoldopam, are independent of changes in systemic blood pressure, in contrast to those of norepinephrine or angiotensin II where intraocular and systemic blood pressures increase in parallel; (3) the ability of a DA1 receptor antagonist to lower intraocular pressure merits investigation.  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