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   52805篇
  免费   6189篇
  国内免费   93篇
耳鼻咽喉   700篇
儿科学   1600篇
妇产科学   1391篇
基础医学   7723篇
口腔科学   1156篇
临床医学   7579篇
内科学   10513篇
皮肤病学   686篇
神经病学   4204篇
特种医学   1615篇
外国民族医学   1篇
外科学   7171篇
综合类   1023篇
一般理论   31篇
预防医学   5596篇
眼科学   794篇
药学   4077篇
中国医学   76篇
肿瘤学   3151篇
  2022年   419篇
  2021年   793篇
  2020年   668篇
  2019年   843篇
  2018年   1110篇
  2017年   860篇
  2016年   1010篇
  2015年   1053篇
  2014年   1389篇
  2013年   2013篇
  2012年   2560篇
  2011年   2581篇
  2010年   1539篇
  2009年   1471篇
  2008年   2236篇
  2007年   2333篇
  2006年   2316篇
  2005年   2294篇
  2004年   2196篇
  2003年   2092篇
  2002年   2049篇
  2001年   1712篇
  2000年   1735篇
  1999年   1536篇
  1998年   709篇
  1997年   591篇
  1996年   496篇
  1995年   533篇
  1994年   496篇
  1993年   462篇
  1992年   1184篇
  1991年   1141篇
  1990年   1108篇
  1989年   1014篇
  1988年   934篇
  1987年   966篇
  1986年   916篇
  1985年   939篇
  1984年   747篇
  1983年   650篇
  1982年   452篇
  1981年   383篇
  1980年   392篇
  1979年   614篇
  1978年   469篇
  1977年   382篇
  1976年   407篇
  1974年   405篇
  1973年   365篇
  1972年   364篇
排序方式: 共有10000条查询结果,搜索用时 6 毫秒
131.
BACKGROUND: The pathophysiology of idiopathic rhinitis is unknown although evidence is accumulating to suggest that many patients may have a localized form of allergic rhinitis in the absence of other atopic symptoms and markers. This study compares detailed nasal challenge results obtained from patients with idiopathic rhinitis to those of atopic and normal controls. METHODS: Patients with idiopathic rhinitis (n = 23), perennial allergic rhinitis (n = 8) and normal controls (n = 8) underwent a normal saline challenge to exclude hyper-reactivity and then bilateral nasal allergen challenges. Nasal patency was assessed by anterior active rhinomanometry. RESULTS: All of the patients with atopic rhinitis demonstrated positive bilateral allergen challenges. All normal control subjects had bilateral negative challenges. Two patients in the idiopathic group tested positively to saline and were excluded from further study with 62% of the remainder testing positive to allergens. Of the idiopathic patients testing positive, 85% were sensitive to house dust mite. CONCLUSION: A significant proportion of patients with idiopathic rhinitis have positive nasal challenges, the vast majority to house dust mite allergen. These findings add to the weight of evidence that suggests 'localized allergy' may exist in the absence of systemic atopic markers.  相似文献   
132.
I contend that although the Luborsky et al. findings on the Dodo bird verdict are noteworthy, the methodology on which they are based is significantly delimited. Amplifying Luborsky et al.'s moderate recognition of that delimitation, I propose a qualitative complement to the extant research. I call this complement "amalgamated" qualitative research and propose that it will deepen, clarify, and contextualize Luborsky et al.'s enigmatic findings. Until this amalgam is implemented, therapy research will be relegated to impressions rather than fine-grained illuminations.  相似文献   
133.
It is unclear whether single and combined pharmacologic inhibition of the renin-angiotensin-aldosterone system have similar effects on endothelial function and blood pressure (BP). The authors evaluated 63 hypertensive patients divided into 4 groups (hydrochlorothiazide 25 mg/d; irbesartan [IRBE] 150 mg/d; quinapril [QUIN] 20 mg/d; or IRBE 150 mg/d + QUIN 20 mg/d) and 25 healthy normotensive subjects (normal) followed for 12 weeks. Endothelium-dependent dysfunction measured as flow-mediated dilation at Weeks 0 and 12 were: normal, 11.5%±2.4% vs 13.5%±2.0%; hydrochlorothiazide, 7.3%±2.0% vs 12.8%±3.1%; QUIN, 7.2%±2.8% vs 13.2%±2.1%; IRBE, 7.1%±2.8% vs 13.0%±2.9%; and IRBE + QUIN, 7.5%±1.9% vs 12.8%±3.0%. Nitroglycerin-mediated responses were: normal, 26.0%±1.9% vs 24.0%±2.5%; hydrochlorothiazide, 17.0%±2.2% vs 18.3%±2.6%; QUIN, 17.8%±3.2% vs 23.4%±3.0%; IRBE, 16.8%±3.6% vs 24.7%±2.0%; and IRBE + QUIN, 17.3%±3.0% vs 25.1%±2.5%. Antihypertensive therapy restored BP to normal and improved the endothelium-dependent and -independent dysfunction after renin-angiotensin-aldosterone system blockade. In a further finding, the combined effect of angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade was not superior to the action of either of these treatments separately.  相似文献   
134.
Results reported are for single dose exposures and refer to 60Co-gamma-irradiation. The RBE determined by V79 cell survival and based on the Do ratio was found to be 1.70 +/- 0.4 ranging from 1.5 to 1.8. In the case of the regeneration of mouse jejunal crypts the RBE was calculated at ten cell survival and was found to be 1.68. The maximum acute mouse skin reaction at a skin score of 2.0 was found to be 2.1 while the average skin reaction was 1.7. Growth retardation of Vicia faba bean roots measured at the level of 50% indicated an average RBE of 3.0 and a range of 2.7 to 3.7. The OER obtained for V79 cell survival was found to be 1.7 to 1.8. Comparison is made with the RBE and OER measurements for the neutron facilities at Clatterbridge, Fermilab and Louvain-la-Neuve which produce neutrons by the same nuclear reaction and whose physical specifications closely resemble those of the Faure neutrons. This comparison indicates that the Faure beam shows no unusual biological features and that its biological effectiveness is in line with that expected from its physical characteristics.  相似文献   
135.
136.
137.
Rats were reared from weaning either in isolation or in social groups for 12 weeks. Potential isolation-related changes in L- and N-type voltage-sensitive calcium channels (VSCCs) were assessed by the in vitro binding of [3H]isradipine (100 pM) and [125I]omega-conotoxin GVIA (4 pM) to membranes prepared from three discrete central nervous system regions: frontal cortex, caudate nucleus and hippocampus. The [3H]isradipine binding was generally not affected by isolation. However, [125I]omega-conotoxin GVIA binding was significantly higher in frontal cortex (52%) and caudate nucleus (75%) of isolated rats when compared with socially reared controls. The increased [125I]omega-conotoxin GVIA binding reflected an elevated density of binding sites without an alteration of receptor affinity. The possible contribution of an increased density of neuronal N-VSCCs (as labeled with [125I]omega-conotoxin GVIA) to the behavioral and neurochemical changes observed in 'isolation syndrome' is discussed.  相似文献   
138.
139.
Numerous techniques have been described for monitoring the postoperative viability of microsurgical free tissue transfers, and their sensitivity and reliability continue to be evaluated in animal experiments and clinical trials. Relative advantages and disadvantages of these various postoperative monitoring techniques are discussed. The concept of intraoperative monitoring of the microsurgical anastomoses during closure and inset of a free flap is introduced because many free flaps may fail on the operating table, but this only becomes clinically apparent several hours later in the early postoperative period.  相似文献   
140.
The strong epidemiologic relationship between specific lipoprotein levels (such as elevated low-density lipoprotein cholesterol or decreased high-density lipoprotein cholesterol) and the future development of coronary heart disease has been well documented. Within the past several years, landmark clinical trials have clearly demonstrated that the incidence of coronary heart disease events is reduced when lipoprotein abnormalities are corrected via pharmacologic therapy. These findings have prompted clinicians to become more vigilant with regard to recognition of dyslipidemias and institution of treatment. This review focuses on the more common primary and secondary dyslipidemias and the currently available lipid-lowering therapies for each disorder. Results of recent coronary angiographic trials are discussed, and implications for the medical management of established coronary heart disease are assessed.  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