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   1406889篇
  免费   101691篇
  国内免费   2453篇
耳鼻咽喉   19911篇
儿科学   45610篇
妇产科学   39972篇
基础医学   203428篇
口腔科学   38137篇
临床医学   122000篇
内科学   278428篇
皮肤病学   28602篇
神经病学   111373篇
特种医学   54578篇
外国民族医学   369篇
外科学   216188篇
综合类   28648篇
现状与发展   2篇
一般理论   487篇
预防医学   104965篇
眼科学   31838篇
药学   107254篇
  3篇
中国医学   2656篇
肿瘤学   76584篇
  2018年   14166篇
  2016年   12054篇
  2015年   14034篇
  2014年   19464篇
  2013年   29839篇
  2012年   41274篇
  2011年   44114篇
  2010年   25856篇
  2009年   24492篇
  2008年   42857篇
  2007年   46285篇
  2006年   46801篇
  2005年   46348篇
  2004年   44501篇
  2003年   43246篇
  2002年   42427篇
  2001年   59835篇
  2000年   61167篇
  1999年   52421篇
  1998年   16005篇
  1997年   14282篇
  1996年   14300篇
  1995年   13558篇
  1994年   12773篇
  1993年   11866篇
  1992年   42069篇
  1991年   41450篇
  1990年   40895篇
  1989年   39631篇
  1988年   36962篇
  1987年   36180篇
  1986年   34577篇
  1985年   33090篇
  1984年   24939篇
  1983年   21784篇
  1982年   13591篇
  1981年   12018篇
  1980年   11154篇
  1979年   23298篇
  1978年   16573篇
  1977年   14377篇
  1976年   13494篇
  1975年   14688篇
  1974年   17166篇
  1973年   16489篇
  1972年   15631篇
  1971年   14492篇
  1970年   13464篇
  1969年   12947篇
  1968年   12164篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
62.
63.
64.
Mucosal trypsin, a protease-activated receptor (PAR) stimulant, may have an endogenous bronchoprotective role on airway smooth muscle. To test this possibility the effects of lumenal trypsin on airway tone in segments of pig bronchus were tested. Bronchial segments from pigs were mounted in an organ chamber containing Kreb's solution. Contractions were assessed from isovolumetric lumen pressure induced by acetylcholine (ACh) or carbachol added to the adventitia. Trypsin, added to the airway lumen (300 microg x mL(-1)), had no immediate effect on smooth muscle tone but suppressed ACh-induced contractions after 60 min, for at least 3 h. Synthetic activating peptides (AP) for PAR1, PAR2 or PAR3 were without effect, but PAR4 AP caused rapid, weak suppression of contractions. Lumenal thrombin was without effect and did not prevent the effects of trypsin. Effects of trypsin were reduced by N(omega)-nitro-L-arginine methyl ester but not indomethacin. Trypsin, thrombin and PAR4 AP released prostaglandin E2. Adventitially, trypsin, thrombin and PAR4 AP (but not PAR2 AP) relaxed carbachol-toned airways after <3 min. The findings of this study show that trypsin causes delayed and persistent bronchoprotection by interacting with airway cells accessible from the lumen. The signalling mechanism may involve nitric oxide synthase but not prostanoids or protease-activated receptors.  相似文献   
65.
The lack of estrogen during menopause is associated with various symptoms including osteoporosis, cardiovascular diseases, and menopausal symptoms. For many years, conventional hormone replacement therapy has been successfully used to treat these conditions. However, in light of recent studies that draw attention to potential hazards of conventional HRT, various attempts were undertaken to search for alternatives of classical HRT. Phytoestrogens are supposed to ameliorate various discomforts associated with menopause. Resveratrol (RES) is present in red wine, grapes and peanuts and has been implicated in cardioprotection and prevention of adverse side effects observed after regular HRT. As the pituitary-thyroid axis is a target of estrogen action, we first assessed the effects of E2 administration on thyroid hormone stimulating hormone releasing hormone (TRH)-induced thyroid stimulating hormone (TSH) secretion from pituitary cell cultures in vitro. Our data reveal that E2 treatment augments the TRH-induced TSH secretion. We furthermore designed a long-term study of three months to assess the effects of subcutaneous and oral administration of 17beta-estradiol (E2), as well as the actions of RES on the pituitary-thyroid axis in ovariectomized (OVX) female rats. Our results demonstrate that serum levels of 1.0 and 8.1 microM RES lead to a significant increase in total serum triiodthyronine (T3) levels. OVX induces TSHbeta mRNA in the adenohypohysis and E2 treatment attenuates this effect. Treatment of rats with subcutaneous implants of E2 does not affect the pituitary-thyroid axis, whereas orally applied E2 benzoate (E2B) increases plasma TSH and total thyroxine (T4) in OVX rats. In all animals, we could not detect changes in thyroid morphology as assessed by hematoxylin-eosin (HE) and Perjod-Acid Schiff's (PAS) staining.  相似文献   
66.
67.
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases.  相似文献   
68.
Is atrial fibrillation an inflammatory disorder?   总被引:2,自引:0,他引:2  
I read with great interest the excellent review on the influenceof inflammation in the pathogenesis of atrial fibrillation (AF)by Boos   相似文献   
69.
70.
Relationship-centered care reflects both knowing and feeling: the knowledge that physician and patient bring from their respective domains of expertise, and the physician’s and patient’s experience, expression, and perception of emotions during the medical encounter. These processes are conveyed and reciprocated in the care process through verbal and nonverbal communication. We suggest that the emotional context of care is especially related to nonverbal communication and that emotion-related communication skills, including sending and receiving nonverbal messages and emotional self-awareness, are critical elements of high-quality care. Although nonverbal behavior has received far less study than other care processes, the current review argues that it holds significance for the therapeutic relationship and influences important outcomes including satisfaction, adherence, and clinical outcomes of care.  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