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   4638篇
  免费   184篇
  国内免费   23篇
耳鼻咽喉   128篇
儿科学   130篇
妇产科学   160篇
基础医学   709篇
口腔科学   14篇
临床医学   265篇
内科学   1188篇
皮肤病学   31篇
神经病学   532篇
特种医学   85篇
外科学   482篇
综合类   44篇
预防医学   241篇
眼科学   118篇
药学   477篇
中国医学   21篇
肿瘤学   220篇
  2023年   15篇
  2022年   81篇
  2021年   126篇
  2020年   46篇
  2019年   73篇
  2018年   86篇
  2017年   67篇
  2016年   70篇
  2015年   105篇
  2014年   135篇
  2013年   156篇
  2012年   282篇
  2011年   301篇
  2010年   170篇
  2009年   120篇
  2008年   262篇
  2007年   337篇
  2006年   334篇
  2005年   336篇
  2004年   367篇
  2003年   342篇
  2002年   264篇
  2001年   45篇
  2000年   26篇
  1999年   43篇
  1998年   29篇
  1997年   38篇
  1996年   29篇
  1995年   26篇
  1994年   17篇
  1993年   25篇
  1992年   26篇
  1991年   15篇
  1990年   22篇
  1989年   18篇
  1988年   27篇
  1987年   18篇
  1986年   19篇
  1985年   17篇
  1984年   30篇
  1983年   25篇
  1982年   19篇
  1981年   16篇
  1979年   19篇
  1977年   16篇
  1976年   14篇
  1975年   17篇
  1974年   15篇
  1972年   18篇
  1965年   17篇
排序方式: 共有4845条查询结果,搜索用时 15 毫秒
81.
Highly purified cannabidiol (CBD) has demonstrated efficacy with an acceptable safety profile in patients with Lennox-Gastaut syndrome or Dravet syndrome in randomized, double-blind, add-on, controlled phase 3 trials. It is important to consider the possibility of drug-drug interactions (DDIs). Here, we review six trials of CBD (Epidiolex/Epidyolex; 100 mg/mL oral solution) in healthy volunteers or patients with epilepsy, which investigated potential interactions between CBD and enzymes involved in drug metabolism of common antiseizure drugs (ASDs). CBD did not affect CYP3A4 activity. Induction of CYP3A4 and CYP2C19 led to small reductions in exposure to CBD and its major metabolites. Inhibition of CYP3A4 activity did not affect CBD exposure and caused small increases in exposure to CBD metabolites. Inhibition of CYP2C19 activity led to a small increase in exposure to CBD and small decreases in exposure to CBD metabolites. One potentially clinically important DDI was identified: combination of CBD and clobazam (CLB) did not affect CBD or CLB exposure, but increased exposure to major metabolites of both compounds. Reduction of CLB dose may be considered if adverse reactions known to occur with CLB are experienced when it is coadministered with CBD. There was a small increase of exposure to stiripentol (STP) when coadministered with CBD. STP had no effect on CBD exposure but led to minor decreases in exposure to CBD metabolites. Combination of CBD and valproate (VPA) did not cause clinically important changes in the pharmacokinetics of either drug, or 2-propyl-4-pentenoic acid. Concomitant VPA caused small increases in exposure to CBD metabolites. Dose adjustments are not likely to be necessary when CBD is combined with STP or VPA. The safety results from these trials were consistent with the known safety profile of CBD. These trials indicate an overall low potential for DDIs between CBD and other ASDs, except for CLB.  相似文献   
82.
BackgroundThe remission of asthma, which is induced during specific immunotherapy (SIT) or appears spontaneously in children is not completely understood and predictors of this phenomenon are still undefined.ObjectiveTo assess CD4+CD25+Foxp3+ Treg cells and cytokine/proliferation response to allergen-specific stimulation of PBMC as predictors of steroid sparing effect of SIT and steroid dosage needs without SIT during 5 years of follow-up in asthmatic children.MethodsThis is a 5-year long study of 32 asthmatic children, sensitive only to house dust mite (HDM). Eighteen children who had completed 5 years of HDM SIT – SIT group, and 14 children without SIT as a control group were studied. All patients had baseline clinical/immunological assessment; before and after observation the minimum effective ICS dose was defined and lung function was measured.ResultsIn children from SIT group minimum effective ICS dose was reduced more than in children from control group (median reduction 65% vs. 0%; p < 0.001). Among patients in control group asthma severity was reduced after 5 years of observation in those who had at baseline higher TGF-beta1 and lower IL-13 answer to allergen stimulation of PBMC. Better response to 5 years immunotherapy was observed in those who had at baseline higher TGF-beta1 and lower proliferation answer to allergen stimulation of PBMC.ConclusionSimilar processes may decide on both, SIT-induced and spontaneously appearing, reduction in asthma severity. Immunotherapy was much more effective than pharmacotherapy in our study. IL-13 overproduction may impede reduction of disease severity in asthmatic children independently from TGF-beta pathway.  相似文献   
83.
Selenium is vital to human health. This article is a compendium of virtually all the published data on total selenium concentrations, its distribution in fruitbody, bioconcentration factors, and chemical forms in wild-grown, cultivated, and selenium-enriched mushrooms worldwide. Of the 190 species reviewed (belonging to 21 families and 56 genera), most are considered edible, and a few selected data relate to inedible mushrooms. Most of edible mushroom species examined until now are selenium-poor (< 1 μ g Se/g dry weight). The fruitbody of some species of wild-grown edible mushrooms is naturally rich in selenium; their occurrence data are reviewed, along with information on their suitability as a dietary source of selenium for humans, the impact of cooking and possible leaching out, the significance of traditional mushroom dishes, and the element's absorption rates and co-occurrence with some potentially problematic elements. The Goat's Foot (Albatrellus pes-caprae) with ~ 200 μ g Se/g dw on average (maximum up to 370 μ g/g dw) is the richest one in this element among the species surveyed. Several other representatives of the genus Albatrellus are also abundant in selenium. Of the most popular edible wild-grown mushrooms, the King Bolete (Boletus edulis) is considered abundant in selenium as well; on average, it contains ~ 20 μ g Se/g dw (maximum up to 70 μ g/g dw). Some species of the genus Boletus, such as B. pinicola, B. aereus, B. aestivalis, B. erythropus, and B. appendiculus, can also accumulate considerable amounts of selenium. Some other relatively rich sources of selenium include the European Pine Cone Lepidella (Amanita strobiliformis), which contains, on average, ~ 20 μ g Se/g dw (up to 37 μ g/g dw); the Macrolepiota spp., with an average range of ~ 5 to < 10 μ g/g dw (an exception is M. rhacodes with < 10 μ g/g dw); and the Lycoperdon spp., with an average of ~ 5 μ g Se/g dw. For several wild-grown species of the genus Agaricus, the selenium content (~ 5 μ g/g dw) is much greater than that from cultivated Champignon Mushroom; these include A. bisporus, A. bitorquis, A. campestris, A. cesarea, A. campestris, A. edulis, A. macrosporus, and A. silvaticus. A particularly rich source of selenium could be obtained from selenium-enriched mushrooms that are cultivated on a substrate fortified with selenium (as inorganic salt or selenized-yeast). The Se-enriched Champignon Mushroom could contain up to 30 or 110 μ g Se/g dw, while the Varnished Polypore (Ganoderma lucidum) could contain up to 72 μ g Se/g dw. An increasingly growing database on chemical forms of selenium of mushrooms indicates that the seleno-compounds identified in carpophore include selenocysteine, selenomethionine, Se-methylselenocysteine, selenite, and several unidentified seleno-compounds; their proportions vary widely. Some aspects of environmental selenium occurrence and human body pharmacokinetics and nutritional needs will also be briefly discussed in this review.  相似文献   
84.
85.
Background: Myocardial ischemia during coronary spasm may generate malignant ventricular arrhythmias. The J‐wave pattern was suggested to be a marker of a disorder associated with life‐threatening arrhythmias. Results: We report the case of a patient with vasospastic angina and J‐wave pattern in inferior and lateral leads associated with polymorphic ventricular tachycardia which was effectively treated only with quinidine—vasodilating drugs were not able to prevent the arrhythmia although they were effective in preventing ischemic events. Conclusion: The J‐wave pattern in inferolateral leads may be a sign of electrical vulnerability to lethal ventricular arrhythmia in patients suffering from vasospastic angina—quinidine can effectively prevent such arrhythmias in these patients.  相似文献   
86.
87.
88.
Usefulness of two-dimensional and Doppler echocardiography in diagnosis of the ruptured interventricular septum in a course of myocardial infarction was evaluated basing on own material consisted of 6 cases. Ventricular septal defect was visualized in 5 patients. The blood flow through the ventricular septum was detected in all of 6 patients. Obtained results were concordant with intraoperative and anatomicopathologic findings as for as the localization of the rupture is concerned.  相似文献   
89.
Sulfonylureas are used in treatment of diabetes. Resistance to these derivatives is a therapeutical problem. Sulfonylureas act through sulfonylurea receptor 1 (SUR1) in the beta cell. SUR1 also enhances a physiological secretion of insulin induced by an increase of glucose concentration. It may be expected that polymorphism of SUR1 gene can lead to beta cell dysfunction and resistance to sulfonylureas. The aim of this study was to examine the frequency of polymorphism in exon 22 of SUR1 gene and its correlation with type 2 diabetes mellitus and sulfonylurea treatment failure. The group consisted of 42 patients with type 2 diabetes. The controls were 46 persons with proper glucose tolerance. Polymorphism was found in 5 patients and in 1 control person. Neither statistically significant difference of polymorphism frequency nor correlation between polymorphism and sulfonylurea failure was found due to a low number of cases. Polymorphism of exon 22 of SUR1 gene appeared more frequent in diabetic than in non-diabetic subjects but this was statistically not significant.  相似文献   
90.
Uroflowmetry is the measurement of a urinary flow rate by using the flow meter. A urine flow rate is the volume of urine (millilitres) expelled from the bladder via the urethra per unit of time (second). It is expressed in ml/s.(1) Urine flow curve is the plot of velocity of the voided urine against time. The urine stream is affected by voiding pressure (detrusor power) and bladder outlet resistance. Therefore, uroflowmetry evaluates the interaction of the urinary bladder expelling strength and bladder outlet resistance. This is the initial, non-invasive urodynamic investigation for evaluation of patients with lower urinary tract symptoms (LUTS). Although, it is very simple and widely used urodynamic test, the results are nonspecific and required caution interpretations. In the next few pages we will review some aspects of this test, i.e. brief history, equipment, indications, procedure itself and interpretation of the results.  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