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   5638篇
  免费   309篇
  国内免费   63篇
耳鼻咽喉   77篇
儿科学   85篇
妇产科学   44篇
基础医学   589篇
口腔科学   109篇
临床医学   345篇
内科学   1469篇
皮肤病学   48篇
神经病学   389篇
特种医学   264篇
外科学   1259篇
综合类   22篇
预防医学   194篇
眼科学   167篇
药学   321篇
中国医学   18篇
肿瘤学   610篇
  2023年   70篇
  2022年   49篇
  2021年   235篇
  2020年   135篇
  2019年   124篇
  2018年   194篇
  2017年   122篇
  2016年   170篇
  2015年   168篇
  2014年   184篇
  2013年   242篇
  2012年   330篇
  2011年   347篇
  2010年   181篇
  2009年   159篇
  2008年   268篇
  2007年   289篇
  2006年   283篇
  2005年   271篇
  2004年   219篇
  2003年   220篇
  2002年   205篇
  2001年   135篇
  2000年   113篇
  1999年   114篇
  1998年   64篇
  1997年   49篇
  1996年   52篇
  1995年   32篇
  1994年   54篇
  1993年   26篇
  1992年   89篇
  1991年   74篇
  1990年   87篇
  1989年   87篇
  1988年   72篇
  1987年   58篇
  1986年   66篇
  1985年   55篇
  1984年   30篇
  1983年   23篇
  1979年   27篇
  1977年   19篇
  1974年   17篇
  1973年   14篇
  1972年   13篇
  1971年   21篇
  1970年   13篇
  1969年   18篇
  1968年   15篇
排序方式: 共有6010条查询结果,搜索用时 234 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.
4.
5.
We present a case of intrapulmonary metastasis developing 18 years after complete resection of thymoma. An 8 mm nodule in the lower lobe of the left lung was noted on chest X-ray in a 76-year-old woman who had undergone complete resection of Masaoka’s stage II thymoma 18 years earlier. Since the nodule grew to 17 mm during a 2-year follow-up, wedge resection was performed. The lesion was histologically diagnosed as an intrapulmonary metastasis from thymoma. Extremely late recurrence after complete resection of thymoma is discussed.  相似文献   
6.
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   
7.
Regional effects of craniotomy on cerebral circulation and metabolism, such as regional cerebral blood flow (rCBF), regional cerebral oxygen consumption (rCMRO2), regional oxygen extraction fraction (rOEF), and regional cerebral blood volume (rCBV) were examined by a PET (positron emission tomography) study concerning surgery that was performed on unruptured aneurysm patients. Eight patients with intracranial un-ruptured aneurysms were studied pre- and post-operatively by the 15O labelled-gas steady-state method, using HEADTOME-III. All patients underwent aneurysmal surgery performed by the transsylvian approach. There was a significant increase in the mean OEF values taken from the whole-brains of 8 patients, but there was not a significant change in CBF, CMRO2 or CBV. The increase in OEF was caused by decrease of O2 content, which was caused by post-operative decrease in the Hb value. So, this OEF increase was not the direct effect of craniotomy. In 2 patients, the rCBF and rCMRO2, in the fronto-temporal region (where craniotomy was performed) increased post-operatively. This regional effect suggests transient reactive hyperemia following compressive ischemia during the operative procedure, and metabolic demands for recovery of brain function. In 2 other patients, who had relatively low rCBFs during the pre-operative study, rCBF and rCMRO2 in the bi-frontal region had decreased more at the post-operative study. This change appears to have been caused by removal of cerebrospinal fluid and depression of the frontal lobe. From this study, it becomes evident that the regional effect of craniotomy on cerebral circulation and metabolism is not so great, when adequate microsurgical techniques are used.  相似文献   
8.
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   
9.
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   
10.
Since humans are under ceaseless orthostatic stress, the mechanism to maintain arterial pressure (AP) under orthostatic stress against gravitational fluid shift is of great importance. We hypothesized that (1) orthostatic stress resets the arterial baroreflex control of sympathetic nerve activity (SNA) to a higher SNA, and (2) resetting of the arterial baroreflex contributes to preventing postural hypotension. Renal SNA and AP were recorded in eight anaesthetized, vagotomized and aortic-denervated rabbits. Isolated intracarotid sinus pressure (CSP) was increased stepwise from 40 to 160 mmHg with increments of 20 mmHg (60 s for each CSP level) while the animal was placed supine and at 60 deg upright tilt. Upright tilt shifted the CSP–SNA relationship (the baroreflex neural arc) to a higher SNA, shifted the SNA–AP relationship (the baroreflex peripheral arc) to a lower AP, and consequently moved the operating point to marked high SNA while maintaining AP. A simulation study suggests that resetting in the neural arc would double the orthostatic activation of SNA and increase the operating AP in upright tilt by 10 mmHg, compared with the absence of resetting. In addition, upright tilt did not change the CSP–AP relationship (the baroreflex total arc). A simulation study suggests that although a downward shift of the peripheral arc could shift the total arc downward, resetting in the neural arc would compensate this fall and prevent the total arc from shifting downward to a lower AP. In conclusion, upright tilt increases SNA by resetting the baroreflex neural arc. This resetting may compensate for the reduced pressor responses to SNA in the peripheral cardiovascular system and contribute to preventing postural hypotension.  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