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   2831篇
  免费   180篇
  国内免费   12篇
耳鼻咽喉   41篇
儿科学   89篇
妇产科学   46篇
基础医学   413篇
口腔科学   173篇
临床医学   196篇
内科学   694篇
皮肤病学   68篇
神经病学   145篇
特种医学   194篇
外国民族医学   1篇
外科学   259篇
综合类   62篇
一般理论   1篇
预防医学   285篇
眼科学   29篇
药学   164篇
中国医学   47篇
肿瘤学   116篇
  2023年   16篇
  2022年   73篇
  2021年   96篇
  2020年   65篇
  2019年   92篇
  2018年   115篇
  2017年   67篇
  2016年   72篇
  2015年   86篇
  2014年   113篇
  2013年   138篇
  2012年   195篇
  2011年   201篇
  2010年   127篇
  2009年   111篇
  2008年   138篇
  2007年   135篇
  2006年   102篇
  2005年   111篇
  2004年   71篇
  2003年   57篇
  2002年   78篇
  2001年   41篇
  2000年   49篇
  1999年   34篇
  1998年   44篇
  1997年   41篇
  1996年   40篇
  1995年   41篇
  1994年   30篇
  1993年   22篇
  1992年   24篇
  1991年   12篇
  1990年   22篇
  1989年   34篇
  1988年   21篇
  1987年   28篇
  1986年   23篇
  1985年   26篇
  1984年   25篇
  1983年   25篇
  1982年   18篇
  1981年   19篇
  1980年   18篇
  1979年   13篇
  1978年   11篇
  1976年   12篇
  1973年   11篇
  1969年   11篇
  1968年   12篇
排序方式: 共有3023条查询结果,搜索用时 41 毫秒
51.
Preclinical and clinical studies show that gastrointestinal (GI) inflammation can evoke sensory changes occasionally far from the original inflammatory site. Animal models of colitis with either trinitrobenzenesulphonic acid (TNBS) or mustard oil (MO) produce distinct patterns of somatic and visceral sensory changes. We evaluated the effects of four doses of i.v. vincristine 150 μg kg?1 (total of 600 μg kg?1) treatment on the somatic (thermal nociceptive threshold) and colonic (morphological) changes induced by TNBS or MO in rats. TNBS and MO groups were further submitted to vincristine or saline pretreatments. TNBS induced somatic hypersensitivity, while MO induced somatic hyposensitivity (P < 0.05) when compared to the saline and ethanol control groups. Vincristine per se induced somatic hypersensitivity (P < 0.05). This effect was enhanced by TNBS and reversed by MO treatments. Although vincristine increased the colitis area (colonic weight length?1 ratio) and the Morris' score in TNBS‐treated rats, it did not alter the colitis area and even lowered the Morris' score in MO‐treated rats. Compared to the saline (control) group, vincristine did not alter the colonic microscopic pattern. However, such lesions scores are higher (P < 0.05) in colitis groups induced by TNBS and MO, pretreated or not with vincristine. In conclusion, the somatic changes induced by different models of experimental colitis are diverse and modulated differently by vincristine.  相似文献   
52.
BACKGROUND: Nosocomial infections (NIs) have become a matter of major concern in neonatal intensive care units (NICUs). The objectives of this study were to determine the incidence rate and the most frequent sites of infection in a Brazilian NICU from January 1999 to March 2000 and to study the risk factors for NIs. METHODS: A cohort study was carried out in which 225 neonates who remained at least 24 hours in the NICU were followed-up; neonates with NIs were identified, and the presence of risk factors was studied. Results were submitted to chi(2) distribution. RESULTS: The incidence rate and the incidence density rate were 50.7% and 62 infections per 1000 patient-days, respectively. In order of frequency, the sites of infection were: pneumonia (40.3%), primary bloodstream (16.7%), skin and soft tissue (14.9%), and meningitis (9.6%). The following risk factors were associated with NIs (P <.05): birth weight, gestational age, mechanical ventilation, total parenteral nutrition, umbilical catheter, use of antibiotics, and intubation in the delivery room. CONCLUSION: Risk factors were similar to those reported by other authors. However, incidence rates of infections in our NICU were much higher, possibly because of different methodologies and the adopted criteria for the classification of NIs.  相似文献   
53.
背景目前已开展了对重性精神病患者进提供连续性服务的研究。目的探讨基层对有抑郁症风险患者提供连续性服务的水平,并与对心力衰竭患者的服务水平进行对比。方法采用抑郁症风险患者与心力衰竭患者对比的探索性研究。采用患者问卷评估服务的持续性,包含如下内容:(1)联系的服务提供者数(个人连续性);(2)诊所内服务提供者之间的合作(团队连续性)(6个项目,分数1~5分);(3)诊所外全科医师与服务提供者之间的合作(跨界连续性)(4个项目,分数1~5分)。结果大多数抑郁症风险患者在过去1年中寻遍整个服务提供界联系了几个服务提供者,曾遇到过高水平团队连续性服务及低水平跨界连续性服务。在诊所中可接触到的不同服务提供者要明显多于心力衰竭患者服务提供者(P<0.01)。抑郁症风险患者的服务提供者之间的合作更好一些,每项平均得分4.3分,心力衰竭患者得分为4.0分(P=0.03)。然而,跨界连续性服务方面正好相反:抑郁症风险患者每项平均得分3.5分,心力衰竭患者得分为4.0分(P=0.01)。结论抑郁症风险患者与心力衰竭患者之间的探索性对比显示:体验服务连续性方面的差距不大。对此还应行进一步分析。  相似文献   
54.

Introduction

Floating right heart thrombi (FRHTS) are a rare phenomenon associated with high mortality. Immediate treatment is mandatory, but optimal therapy is controversial.

Objective

To compare the clinical characteristics according to different treatment strategies and to identify predictors of mortality on patients with FRHTS.

Methods

We conducted a systematic search of reported clinical cases of TTRH from 2006 to 2016.

Results

207 patients were analyzed, median age was 60 years, 51.7% were men, 31.4% presented with shock. Pulmonary thromboembolism was present in 85% of the cases. The treatments administered were anticoagulation therapy in 44 patients (21.28%), surgical embolectomy in 89 patients (43%), thrombolytic therapy in 66 patients (31.8%), percutaneous thrombectomy in 3 patients (1.93%) and fibrinolytic in situ in 4 (1.45%). The overall mortality rate was 21.3%. The mortality associated with anticoagulation alone was higher than surgical embolectomy or thrombolysis (36.4 vs 18% vs 18.2%, respectively, p = 0.03), and in percutaneous thrombectomy and fibrinolytics in situ was 0%. At multivariate analysis, only anticoagulation alone (odds ratio [OR] 2.4, IC 95% 1.07–5.4, p = 0.03), and shock (OR 2.87 (IC 95% 1.3–5.9, p = 0.005) showed a statistically significant effect on mortality.

Conclusion

FRHTS represent a serious form of thromboembolism that requires rapid decisions to improve the survival. Anticoagulation as the only strategy does not seem to be sufficient, while thrombolysis and surgical thrombectomy show better and similar results. A proper individualization of the risk and benefits of both techniques is necessary to choose the most appropriate strategy for our patients.  相似文献   
55.
56.
57.
We compared the impact of low and high-pressure balloon inflation on acute and late angiographic results of Multilink stent. Low-pressure balloon inflation (9.5 +/- 1.9 atm) was used in 43 stents and high pressure (17.1 +/- 1.5 atm) in 44. A larger immediate luminal gain was achieved in stents with high-pressure balloon inflation (1.80 +/- 0.26 vs. 1.47 +/- 0.62; P = 0.002), resulting in a larger mean diameter in this group (2.71 +/- 0.37 vs. 2.48 +/- 0.47; P = 0.017). At follow-up, a larger luminal diameter was achieved in the high pressure group (1.93 +/- 0.72 vs. 1.45 +/- 0.66; P = 0.002) and a trend to a lower rate of angiographic restenosis (15% vs. 38%, P = 0.08).  相似文献   
58.
59.
60.
The pilocarpine model in rodents reproduces the main features of mesial temporal lobe epilepsy related to hippocampus sclerosis (MTLE-HS) in humans. It has been demonstrated in this model that the phosphorylation of the alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluR1 subunit is increased 1 h after pilocarpine treatment. Moreover, alterations in the levels of glutamate transporters have been associated with chronic epilepsy in humans. Despite these studies, the profile of these changes has not yet been addressed. We analyzed the protein content and phosphorylation profile of the AMPA receptor GluR1 subunit by western blotting. We also used quantitative real-time polymerase chain reaction to analyze the expression of glial glutamate transporters and the N-methyl-d-aspartate receptor NR1 subunit in the hippocampus (Hip) and cerebral cortex (Ctx) at different time points after pilocarpine-induced status epilepticus (Pilo-SE) in male adult Wistar rats. Biochemical analysis was performed in the Hip and Ctx at 1, 3, 12 h (acute period), 5 days (latent period), and 50 days (chronic period) after Pilo-SE. Key findings include an increase in the phosphorylation of GluR1-Ser845 in the Ctx and GluR1-Ser831 in the Hip at different times during the acute period, and a decrease in the total content of the GluR1 subunit in the Ctx in the latent period. There was a down-regulation of the mRNA expression and protein levels of EAAT1 and EAAT2, and a decrease of the NR1 mRNA expression, in the Ctx during the latent period. Notably, during the chronic period, the EAAT2 mRNA expression and protein levels decreased while the NR1 mRNA levels increased in the Hip. Taken together, our findings suggest a time- and structure-dependent imbalance of glutamatergic transmission in response to Pilo-SE, which might be associated with either epileptogenesis or the seizure threshold in MTLE-HS.  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