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   3338篇
  免费   208篇
  国内免费   37篇
耳鼻咽喉   17篇
儿科学   33篇
妇产科学   31篇
基础医学   414篇
口腔科学   54篇
临床医学   231篇
内科学   895篇
皮肤病学   38篇
神经病学   237篇
特种医学   108篇
外科学   558篇
综合类   7篇
预防医学   107篇
眼科学   64篇
药学   431篇
中国医学   10篇
肿瘤学   348篇
  2024年   5篇
  2023年   51篇
  2022年   88篇
  2021年   179篇
  2020年   93篇
  2019年   85篇
  2018年   135篇
  2017年   81篇
  2016年   107篇
  2015年   106篇
  2014年   103篇
  2013年   155篇
  2012年   218篇
  2011年   239篇
  2010年   118篇
  2009年   103篇
  2008年   168篇
  2007年   189篇
  2006年   182篇
  2005年   191篇
  2004年   145篇
  2003年   133篇
  2002年   148篇
  2001年   51篇
  2000年   62篇
  1999年   66篇
  1998年   40篇
  1997年   26篇
  1996年   31篇
  1995年   22篇
  1994年   21篇
  1993年   10篇
  1992年   23篇
  1991年   26篇
  1990年   17篇
  1989年   19篇
  1988年   19篇
  1987年   17篇
  1986年   19篇
  1985年   18篇
  1984年   8篇
  1983年   14篇
  1982年   6篇
  1979年   3篇
  1978年   3篇
  1975年   6篇
  1973年   4篇
  1972年   3篇
  1970年   3篇
  1969年   5篇
排序方式: 共有3583条查询结果,搜索用时 109 毫秒
1.
BACKGROUND Minimally invasive surgery for gastric cancer(GC) has gained widespread use as a safe curative procedure especially for early GC.AIM To determine risk factors for postoperative complications after minimally invasive gastrectomy for GC.METHODS Between January 2009 and June 2019, 1716 consecutive patients were referred to our division for primary GC. Among them, 1401 patients who were diagnosed with both clinical and pathological Stage Ⅲ or lower GC and underwent robotic gastrectomy(RG) or laparoscopic gastrectomy(LG) were enrolled. Retrospective chart review and multivariate analysis were performed for identifying risk factors for postoperative morbidity.RESULTS Morbidity following minimally invasive gastrectomy was observed in 7.5% of the patients. Multivariate analyses demonstrated that non-robotic minimally invasive surgery, male gender, and an operative time of ≥ 360 min were significant independent risk factors for morbidity. Therefore, morbidity was compared between RG and LG. Accordingly, propensity-matched cohort analysis revealed that the RG group had significantly fewer intra-abdominal infectious complications than the LG group(2.5% vs 5.9%, respectively; P = 0.038), while no significant differences were noted for other local or systemic complications.Multivariate analyses of the propensity-matched cohort revealed that non-robotic minimally invasive surgery [odds ratio = 2.463(1.070–5.682); P = 0.034] was a significant independent risk factor for intra-abdominal infectious complications.CONCLUSION The findings showed that robotic surgery might improve short-term outcomes following minimally invasive radical gastrectomy by reducing intra-abdominal infectious complications.  相似文献   
2.
3.
This cross-sectional study was conducted to examine whether the obstructive sleep apnea syndrome (OSAS) is associated with elevation of the pulse wave velocity (PWV) and increase in the plasma levels of C-reactive protein (CRP), both of which are known markers of cardiovascular risk, and also to determine if the concurrent presence of the metabolic syndrome might exacerbate this elevation in the levels of these cardiovascular risk markers in subjects with OSAS. With these objectives, the PWV and serum CRP were measured in 184 subjects attending a sleep clinic. It was found that the PWV and CRP were higher in the subjects with OSAS (n=94) than in those without OSAS (n=90). Furthermore, among the subjects with OSAS, the PWV and CRP were higher in those with the concurrent presence of the metabolic syndrome (n= 41; PWV=1,562+/-19 cm/s; CRP=1.8+/-0.2 mg/l) than in those without metabolic syndrome (n=53; PWV=1,432+/-21 cm/s; CRP=1.2+/-0.1 mg/l) (p<0.05). A general linear model analysis demonstrated that OSAS and metabolic syndrome were independently associated with elevated PWV and increase of the plasma levels of CRP. OSAS appears to be associated with increased cardiovascular risk, as reflected by both elevated PWV and increase of the plasma CRP. The concurrent presence of metabolic syndrome may exacerbate this increase in cardiovascular risk in subjects with OSAS. Therefore, the concurrent presence of metabolic syndrome may constitute an additive cardiovascular risk factor in subjects with OSAS.  相似文献   
4.
目的评估十二指肠-空肠导管(Endoluminal Duodeno-Jejunal Tube,EDJT)在活体猪实验动物模型中减缓体重增加的可行性,及其在中短期生存中的安全性。方法本项研究共用8只45kg重的Yorkshire猪,其中3只置入180emEDJT,1只置入360cm EDJT,另4只猪作为对照组。切开十二指肠,将EDJT导管缝合固定在十二指肠近Vater壶腹起始处。结果评估全部猪的不适反应和体重,每日一次,共7周,未发现严重并发症发生。术后7周3组动物的平均体重变化百分率:对照组、180cm组和360cm组分别是22.5%,6%和-2.8%。EDJT组(180cm组、360cm组)体重增加明显减慢,与对照组相比,有统计学意义(P=0.05)。结论EDJT可以安全使用,无肠梗阻、肠套叠或胰腺炎等并发症发生。EDJT可明显减缓体重增加。  相似文献   
5.
This observational study of Japanese men without metabolic syndrome (MetS) (age: 41+/-8 years) was conducted to clarify whether or not heart rate elevation precedes the development of full-blown MetS. MetS was defined based on two modifications of the criteria of the Japanese Expert Committee on the Diagnosis and Classification of Metabolic Syndrome. Premetabolic syndrome subjects were defined as those having one component of MetS with increased body mass index (BMI). Among the subjects without MetS (n=1,859 when the BMI criterion was >or=25 and n=2,020 when the BMI criterion was >or=27.5), the incidence of progression to full-blown MetS by the time of the second examination at the end of the 3-year study period was higher in the subjects with premetabolic syndrome than in those without it. The receiver-operator characteristic curve analysis and binary logistic regression analysis revealed that the odds ratio (OR) of a heart rate >or=69 beats/min at the first examination for progression to full-blown MetS by the time of the second examination was significant in subjects with premetabolic syndrome (BMI>or=25: OR=3.64 [1.22-10.88]; BMI>or=27.5: OR=3.67 [1.28-10.55]; p<0.05). Thus, heart rate elevation appears to precede the development of full-blown MetS in subjects with premetabolic syndrome. Heart rate seems to be a simple and useful marker for predicting the progression to full-blown MetS of middle-aged Japanese men with premetabolic syndrome.  相似文献   
6.
We examined the involvement of GABAergic neuronal systems in benzodiazepine-induced passive avoidance deficit. Chlordiazepoxide impaired the passive avoidance response dose dependently when it was given prior to training. Post-training administration of muscimol improved the performance of chlordiazepoxide-pretreated mice. The effects of muscimol were antagonized completely by the GABAA antagonist, bicuculline, and the muscarinic acetylcholine receptor antagonist, scopolamine, but not by the benzodiazepine receptor antagonist, flumazenil, when the latter was administered immediately after training. It appears from these results that the GABAergic neuronal system plays an important role in the benzodiazepine-induced passive avoidance deficit by interacting with the cholinergic neuronal system.  相似文献   
7.
Background : Fission yeast microtubule associating protein (MAP) p93Dis1 functions for sister chromatid separation: dis1 mutants fail to separate chromosomes, while the spindle elongates but without cyclin destruction. p93Dis1 localizes along microtubules in interphase cytoplasm, but shifts to the spindle pole body (SPB) and spindle microtubules upon the entry into mitosis. In this study, regions of p93Dis1 were dissected to examine their role.
Results : Nitrocellulose filter blotting shows that recombinant Dis1 binds to bovine brain microtubules in vitro . A basic central region rich in S, T and P is essential for this association. However, the whole p93Dis1 with N- and C-termini containing a conserved repeat motif and heptad repeats, respectively, is necessary for normal microtubule association in vivo . The N-truncated region also binds to microtubules but only to the portions near the SPBs. Overproduction phenotypes indicate that p93Dis1 greatly affects spindle formation and cell morphogenesis. The central region is essential but, by itself, not sufficient for generating such effects.
Conclusions : We propose that p93Dis1 consists of three regions which carry distinct properties for localization: the N-region for cell cycle dependent localization, the central region for direct microtubule association, and the C-region for SPB and nuclear localization. The essential role of p93Dis1 is carried out in the C-region, while the N-region acts as a regulator.  相似文献   
8.
The effects of N-(2,6-dimethyl-phenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide (DM-9384), a new pyrrolidone derivative, were investigated on ethanol- and chlordiazepoxide (CDP)-induced amnesia animal model using the passive avoidance task in comparison with aniracetam, another pyrrolidone derivative. Pretraining administration of DM-9384 attenuated ethanol- and CDP-induced amnesia, whereas aniracetam failed to do so. The effects of DM-9384 on CDP-induced amnesia were antagonized by bicuculline, a GABAA receptor antagonist, but not by scopolamine, a muscarinic acetylcholine receptor antagonist and flumazenil, a benzodiazepine receptor antagonist. These results suggest that DM-9384 attenuates CDP-induced amnesia by interacting with the GABAergic neuronal system.  相似文献   
9.
To determine postoperative refractive errors of secondary intraocular lens (IOL) implantation, this study was performed in 42 eyes of 42 patients following secondary IOL implantation fixed in the sulcus after simultaneous vitrectomy and phacoemulsification and aspiration. Controls were 138 eyes of 124 patients with cataract who underwent phacoemulsification and aspiration and IOL implantation. The spread between expected and actual refraction (actual - expected) was -0.81 +/- 0.86 diopters (average +/- standard deviation) in the study group and 0.01 +/- 0.91 diopters in the control group (statistically significant, P < .001, Student's t test). The actual refractive errors in the study subjects were shifted toward myopia compared with the controls.  相似文献   
10.
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