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   3534篇
  免费   192篇
  国内免费   26篇
耳鼻咽喉   29篇
儿科学   50篇
妇产科学   95篇
基础医学   410篇
口腔科学   182篇
临床医学   257篇
内科学   779篇
皮肤病学   111篇
神经病学   395篇
特种医学   120篇
外科学   551篇
综合类   30篇
预防医学   279篇
眼科学   41篇
药学   183篇
中国医学   21篇
肿瘤学   219篇
  2023年   22篇
  2022年   18篇
  2021年   96篇
  2020年   52篇
  2019年   75篇
  2018年   97篇
  2017年   75篇
  2016年   60篇
  2015年   88篇
  2014年   147篇
  2013年   148篇
  2012年   256篇
  2011年   280篇
  2010年   165篇
  2009年   132篇
  2008年   253篇
  2007年   231篇
  2006年   205篇
  2005年   185篇
  2004年   181篇
  2003年   158篇
  2002年   169篇
  2001年   57篇
  2000年   59篇
  1999年   51篇
  1998年   23篇
  1997年   34篇
  1996年   21篇
  1995年   16篇
  1994年   12篇
  1993年   9篇
  1992年   34篇
  1991年   23篇
  1990年   27篇
  1989年   34篇
  1988年   17篇
  1987年   17篇
  1986年   20篇
  1985年   18篇
  1984年   20篇
  1983年   19篇
  1982年   11篇
  1980年   12篇
  1979年   16篇
  1976年   10篇
  1974年   8篇
  1973年   10篇
  1972年   8篇
  1971年   8篇
  1969年   8篇
排序方式: 共有3752条查询结果,搜索用时 15 毫秒
1.
2.
We report on a 3‐year‐old girl with a microvesicular generalized rash in whom primary infection by parvovirus B19 was demonstrated by seroconversion. To our knowledge, this is the first instance of an eruption arising from parvovirus B19 with this peculiar clinical pattern.  相似文献   
3.
The American public is increasingly concerned about risks associated with food additives like high-fructose corn syrup (HFCS). To promote its product as safe, the Corn Refiners Association (CRA) employed two forms of straw-person arguments. First, the CRA opportunistically misrepresented HFCS opposition as inept. Second, the CRA strategically chose to refute claims that were easier to defeat while remaining ambiguous about more complex points of contention. We argue that CRA’s discursive contributions represented unreasonable yet sustainable use of straw-person arguments in debates surrounding health and risk.  相似文献   
4.
The aim was to evaluate sentinel node detection capacity by means of a magnetic probe in 11 patients with oral squamous cell carcinoma at stages T1-T2 received submucosal injections of a superparamagnetic iron oxide contrast agent (SPIO). A magnetic probe was used for sentinel node biopsy. The use of SPIO and magnetic probes in the early stages of oral cancer may offer an alternative to conventional radioisotope techniques and/or elective neck dissection.  相似文献   
5.
CB2 receptors (CB2R) are expressed in midbrain neurons. To evidence the control of dopamine release in dorsal striatum by CB2R, we performed experiments of [3H]-dopamine release in dorsal striatal slices. We found a paradoxical increase in K+-induced [3H]-dopamine release by CB2R activation with GW 833972A and JWH 133 two selective agonist. To understand the mechanism involved, we tested for a role of the D2 autoreceptor in this effect; because in pallidal structures, the inhibitory effect of CB1 receptors (CB1R) on GABA release is switched to a stimulatory effect by D2 receptors (D2R). We found that the blockade of D2 autoreceptors with sulpiride prevented the stimulatory effect of CB2R activation; in fact, under this condition, CB2R decreased dopamine release, indicating the role of the D2 autoreceptor in the paradoxical increase. We also found that the effect occurs in nigrostriatal terminals, since lesions with 6-OH dopamine in the middle forebrain bundle prevented CB2R effects on release. In addition, D2–CB2R interaction promoted cAMP accumulation, and the increase in [3H]-dopamine release was prevented by PKA blockade. D2–CB2R coprecipitation and proximity ligation assay studies indicated a close interaction of receptors that could participate in the observed effects. Finally, intrastriatal injection of CB2R agonist induced contralateral turning in amphetamine-treated rats, which was prevented by sulpiride, indicating the role of the interaction in motor behavior. Thus, these data indicate that the D2 autoreceptor switches, from inhibitory to stimulatory, the CB2R effects on dopamine release, involving the cAMP → PKA pathway in nigrostriatal terminals.  相似文献   
6.
IntroductionAlthough changes in liver function tests can be non-specific in numerous clinical conditions, they can be the first sign of a potentially serious disease in an asymptomatic patient.Material and methodsRetrospective cohort study, performed by reviewing the records of children of a reference hospital central laboratory with alanine aminorransferase enzyme (ALT) elevation during a 6 month aleatory period.Results572 blood tests with serum ALT elevation corresponding to 403 patients had been assessed during the period studied. 98 patients were excluded for presenting abnormal liver test before the study period of comorbidity that could produce ALT elevation. The remaining 305 patients, 22.6% were diagnosed with a medical condition during the first blood test that explained the ALT elevation, although only 33.3% of them were followed up until verifying their normalization. Final study sample consists of 236 patients with abnormal liver test without apparent liver disease. Adequate follow-up was found only in 29% of them. From this group, 9 patients (13%) were diagnosed with liver disease. The rest of the sample were not properly monitored. In patients with higher serum ALT levels, follow-up was early and more appropiate.ConclusionsIn our area, most children without apparent liver disease are no properly monitored. Therefore, an opportunity to diagnosis and treat a potential liver disease was lost in a great number of children. All children with unexplainedhypertransaminasaemia must be studied.  相似文献   
7.
The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis, prevention and cure of the disease. The combined work of three researchers, Alter H, Houghton M and Rice C, which set the basis for the diagnosis, treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents. This is a story of a transfusion-associated infection. A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis. That was followed by the identification of what was later known to be the hepatitis C virus (HCV) and the development of diagnostic tests. It all preceded the full molecular identification and demonstration of a causal effect. Finally it ended up with the development and discovery of a new class of therapeutic drugs, the direct acting antivirals, which are now used not only to cure the disease but most probably, to eliminate the problem. This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus. Finally, the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans.  相似文献   
8.
9.
End‐stage renal disease is a cause for death worldwide. Renal transplant is a therapeutic alternative, restricted by the scant number of donors. Function of the donor kidney is under risk of adverse circumstances such as fibrosis, where profibrotic effect of transforming growth factor beta 1 (TGF‐β1) plays a key role. Efforts to diminish risks of damage in the remnant kidney of the donor are required. Vitamin A represents one alternative. It has beneficial effects on some nephropathies, mainly those related to oxidative stress. It also participates in normal intrauterine renal development. We studied the effect of all‐trans retinoic acid (ATRA), active form of vitamin A, on postnephrectomy compensatory growth, in male or female rats. Compensatory growth and renal function were evaluated on four experimental groups: Control without treatment (CTL), ATRA‐treated intact rats (CTL + RA), nephrectomized rats (NFX), and ATRA‐treated nephrectomized rats (NFX + RA). We evaluated glomerular function (inulin clearance), tubular function (fractional excretions of sodium and potassium), and urinary flow. Renal mass was also estimated. In ATRA‐treated animals, compensatory growth was higher than in nephrectomized rats without treatment. Hyperfiltration after nephrectomy was less intense in ATRA‐treated female than in male rats. In tubular functions, effect of ATRA was more evident in female than in male rats. Glomerular expression of TGF‐β1 was lower in ATRA‐treated animals than in controls. ATRA reduced intensity and duration of compensatory changes after nephrectomy, improving recovery.  相似文献   
10.
Steroids are drugs that have been used extensively in a variety of conditions. Although widely prescribed for their anti-inflammatory and immunosuppressive properties, glucocorticoids have several side effects, being hyperglycemia one of the most common and representative. In the present review, we discuss the main epidemiologic characteristics associated with steroid use, with emphasis on the identification of high risk populations. Additionally we present the pathophysiology of corticosteroid induced hyperglycemia as well as the pharmacokinetics and pharmacodynamics associated with steroid use. We propose a treatment strategy based on previous reports and the understanding of the mechanism of action of both, the different types of glucocorticoids and the treatment options, in both the ambulatory and the hospital setting. Finally, we present some of the recent scientific advances as well as some options for future use of glucocorticoids.  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