全文获取类型
收费全文 | 21279篇 |
免费 | 1390篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 148篇 |
儿科学 | 470篇 |
妇产科学 | 280篇 |
基础医学 | 2773篇 |
口腔科学 | 341篇 |
临床医学 | 2653篇 |
内科学 | 3782篇 |
皮肤病学 | 202篇 |
神经病学 | 1892篇 |
特种医学 | 734篇 |
外科学 | 2915篇 |
综合类 | 244篇 |
一般理论 | 28篇 |
预防医学 | 2725篇 |
眼科学 | 438篇 |
药学 | 1681篇 |
中国医学 | 36篇 |
肿瘤学 | 1387篇 |
出版年
2024年 | 20篇 |
2023年 | 138篇 |
2022年 | 246篇 |
2021年 | 496篇 |
2020年 | 317篇 |
2019年 | 450篇 |
2018年 | 523篇 |
2017年 | 397篇 |
2016年 | 444篇 |
2015年 | 592篇 |
2014年 | 762篇 |
2013年 | 985篇 |
2012年 | 1683篇 |
2011年 | 1705篇 |
2010年 | 968篇 |
2009年 | 907篇 |
2008年 | 1500篇 |
2007年 | 1634篇 |
2006年 | 1475篇 |
2005年 | 1491篇 |
2004年 | 1449篇 |
2003年 | 1367篇 |
2002年 | 1175篇 |
2001年 | 153篇 |
2000年 | 131篇 |
1999年 | 188篇 |
1998年 | 227篇 |
1997年 | 158篇 |
1996年 | 138篇 |
1995年 | 112篇 |
1994年 | 118篇 |
1993年 | 94篇 |
1992年 | 64篇 |
1991年 | 50篇 |
1990年 | 46篇 |
1989年 | 52篇 |
1988年 | 36篇 |
1987年 | 54篇 |
1986年 | 35篇 |
1985年 | 35篇 |
1984年 | 37篇 |
1983年 | 40篇 |
1982年 | 32篇 |
1981年 | 38篇 |
1980年 | 31篇 |
1979年 | 27篇 |
1978年 | 20篇 |
1977年 | 11篇 |
1976年 | 16篇 |
1975年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
File TM Jacobs MR Poole MD Wynne B; Clinical Study Groups 《International journal of antimicrobial agents》2002,20(4):235-247
The efficacy of a new pharmacokinetically enhanced formulation of amoxycillin/clavulanate (AMX/CA) 2000/125 mg, twice daily, designed to provide adequate levels of amoxycillin over the 12-h dosing interval to eradicate penicillin-resistant Streptococcus pneumoniae (PRSP) with amoxycillin (+/-clavulanic acid) MICs of =4 mg/l, was evaluated in patients with respiratory infections caused by S. pneumoniae, including PRSP (penicillin MICs 2-16 mg/l). Data from nine clinical studies were combined (total intent-to-treat N=5531). Six randomized, double-blind studies used levofloxacin 500 mg od in acute bacterial sinusitis (ABS), levofloxacin 500 mg od in acute exacerbations of chronic bronchitis (AECB), clarithromycin 500 mg bid in AECB, AMX/CA 875/125 mg bid and tid in community-acquired pneumonia (CAP) and AMX/CA 1000/125 mg tid in CAP as comparators. The three remaining studies (two in ABS and one in CAP) were non-comparative. In the AMX/CA 2000/125 mg bid-treated patients evaluable at follow-up (Day 14-39), outcome was successful in 60/64 (93.7%) patients with S. pneumoniae infections in the comparative studies and 348/363 (95.9%) in the non-comparative studies, including 95.6% of all patients and 95.2% of patients whose isolates had AMX/CA MICs of >/=4 mg/l. In the pooled comparator group, the success rate at follow-up was 86.5% (45/52). For PRSP (AMX/CA MICs of 0.5-8 mg/l), the overall success rate was 98.2% (55/56) at follow-up for AMX/CA 2000/125 mg and 50.0% (2/4) for comparators. AMX/CA 2000/125 mg shows efficacy comparable to that of the comparators evaluated against S. pneumoniae infections. Due to its favorable pharmacokinetic/pharmacodynamic profile and promising clinical success, the new AMX/CA 2000/125 mg formulation should be considered for the empirical treatment of respiratory tract infections in regions with a high prevalence of antimicrobial-resistant S. pneumoniae and in patients at high risk of antimicrobial-resistant S. pneumoniae infection as this formulation covers many PRSP that are non-susceptible to amoxycillin (+/-clavulanic acid) (MICs of >/=4 mg/l) as well as common beta-lactamase-producing respiratory pathogens. 相似文献
942.
Croup, or laryngotracheobronchitis, is a common childhood illness most often caused by viral infections. It is usually a benign, self-limiting disease, but can result in life-threatening upper airway obstruction. Until recently, it was not uncommon for children with severe croup to be admitted to intensive care for intubation. Management used to be limited to supportive measures, including mist therapy. The use of corticosteroids in patients with croup was controversial for many years but has, in the last decade, transformed the management of this disorder. Although corticosteroids do not alter the history of the viral infection, an adequate dose of oral or parenteral dexamethasone or nebulized budesonide has been shown to have a beneficial effect on the symptoms of croup. 相似文献
943.
944.
945.
946.
947.
Taylor MS Bonev AD Gross TP Eckman DM Brayden JE Bond CT Adelman JP Nelson MT 《Circulation research》2003,93(2):124-131
The endothelium is a critical regulator of vascular tone, and dysfunction of the endothelium contributes to numerous cardiovascular pathologies. Recent studies suggest that apamin-sensitive, small-conductance, Ca2+-activated K+ channels may play an important role in active endothelium-dependent vasodilations, and expression of these channels may be altered in disease states characterized by vascular dysfunction. Here, we used a transgenic mouse (SK3T/T) in which SK3 expression levels can be manipulated with dietary doxycycline (DOX) to test the hypothesis that the level of expression of the SK subunit, SK3, in endothelial cells alters arterial function and blood pressure. SK3 protein was elevated in small mesenteric arteries from SK3T/T mice compared with wild-type mice and was greatly suppressed by dietary DOX. SK3 was detected in the endothelium and not in the smooth muscle by immunohistochemistry. In whole-cell patch-clamp experiments, SK currents in endothelial cells from SK3T/T mice were almost completely suppressed by dietary DOX. In intact arteries, SK3 channels contributed to sustained hyperpolarization of the endothelial membrane potential, which was communicated to the arterial smooth muscle. Pressure- and phenylephrine-induced constrictions of SK3T/T arteries were substantially enhanced by treatment with apamin, suppression of SK3 expression with DOX, or removal of the endothelium. In addition, suppression of SK3 expression caused a pronounced and reversible elevation of blood pressure. These results indicate that endothelial SK3 channels exert a profound, tonic, hyperpolarizing influence in resistance arteries and suggest that the level of SK3 channel expression in endothelial cells is a fundamental determinant of vascular tone and blood pressure. 相似文献
948.
949.
Stanniocalcin (STC) is a new mammalian polypeptide hormone and appears to be a regulator of neuronal function. We have already shown that the induction of STC mRNA and protein expression by cAMP is integral to neuroblastoma cell differentiation, particularly neurite outgrowth. In this study, we examined the cAMP pathway in greater detail. Some common neuritogenic agents, euxanthone (PW1) and trans-retinoic acid (RA), were studied for possible interactions with the dibutyryl cAMP (dbcAMP)-mediated response. Our results showed that STC mRNA induction by dbcAMP was mediated by protein kinase A-cAMP response element binding protein (CREB) pathway, accompanied with phosphorylation of CREB and a reduction of p50, p65, and phosphorylated inhibitor kappaBalpha levels. Using a synthetic peptide nuclear factor-kappaB SN50, stimulation of dbcAMP-mediated STC expression was observed; indicating the nuclear translocation of nuclear factor kappaB might possibly repress STC expression. dbcAMP-induced STC mRNA expression was enhanced by PW1. In contrast, RA had highly suppressive effects. Cotreatment of cell with PW1 and cAMP provoked an increase in phosphorylated CREB (pCREB). Conversely, cotreatment with RA suppressed pCREB. The results highlighted the importance of phosphorylation of CREB in mediating STC gene expression. Taking a step further to dissect the possible regulatory pathways involved, with the aid of phorbol 12-myristate 13-acetate or ionomycin, additive effects on STC gene expression were observed. The induction was aided by further elevation of pCREB, which was completely abolished by G? 6976, a Ca2+-dependent protein kinase C (PKC) alpha and PKCbeta1 inhibitor. Our results indicated that cross-talk with PKC and/or Ca2+ signaling pathways might sensitize cAMP-mediated effects, on CREB phosphorylation and STC gene expression. 相似文献
950.
OBJECTIVE: In a group of crime victims, the authors investigated overlap between acute stress disorder and posttraumatic stress disorder (PTSD) diagnoses and their relative ability to predict PTSD at 6 months. METHOD: A mixed-sex group of 157 victims of violent assault were interviewed within 1 month of the crime. At the 6-month follow-up, 87.9% were reinterviewed by telephone. RESULTS: At baseline the rate of acute stress disorder was 19.1%, the rate of PTSD was 21.0%, and the percentage agreement between them was 95.5%. The two diagnoses were equally effective predictors of PTSD 6 months later. CONCLUSIONS: The high level of overlap between acute stress disorder and PTSD calls into question whether, as presently formulated, they represent distinct diagnoses. 相似文献