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   1891篇
  免费   81篇
  国内免费   6篇
耳鼻咽喉   14篇
儿科学   45篇
妇产科学   15篇
基础医学   219篇
口腔科学   28篇
临床医学   111篇
内科学   304篇
皮肤病学   18篇
神经病学   195篇
特种医学   53篇
外科学   304篇
综合类   7篇
预防医学   37篇
眼科学   89篇
药学   399篇
中国医学   3篇
肿瘤学   137篇
  2023年   10篇
  2022年   29篇
  2021年   39篇
  2020年   31篇
  2019年   23篇
  2018年   37篇
  2017年   23篇
  2016年   37篇
  2015年   39篇
  2014年   41篇
  2013年   48篇
  2012年   68篇
  2011年   68篇
  2010年   48篇
  2009年   58篇
  2008年   89篇
  2007年   98篇
  2006年   85篇
  2005年   92篇
  2004年   85篇
  2003年   79篇
  2002年   65篇
  2001年   73篇
  2000年   84篇
  1999年   81篇
  1998年   16篇
  1997年   17篇
  1996年   13篇
  1995年   12篇
  1994年   8篇
  1993年   8篇
  1992年   58篇
  1991年   48篇
  1990年   47篇
  1989年   46篇
  1988年   45篇
  1987年   30篇
  1986年   28篇
  1985年   20篇
  1984年   23篇
  1983年   16篇
  1982年   11篇
  1980年   6篇
  1979年   20篇
  1978年   11篇
  1977年   7篇
  1974年   7篇
  1971年   7篇
  1970年   5篇
  1969年   7篇
排序方式: 共有1978条查询结果,搜索用时 140 毫秒
71.
Regional progression of neurofibrillary tangles (NFTs) around the hippocampus was traced on thick sections double immunofluorolabeled with RD3 and RD4 antibodies, specific for three- and four-repeat tau, respectively. As reported, the cubic density of all tau-positive neurons was predominant in the entorhinal cortex and cornu ammonis (CA)1, and decreased progressively to the CA2–4 subregions. Among the three isoform profiles (RD3+/4?, RD3+/4+, and RD3?/4+), this regional gradient was replicated with RD3+/4? and RD3+/4+ neurons, while RD3?/4+ neurons exhibited the reverse gradient. Comparison of the subregion pairs confirmed a consistent profile shift along this gradient in every case regardless of the abundance of NFTs. To clarify the underlying mechanism of this regional profile shift, intraneuronal intensity of RD3 and RD4 immunoreactivity (IR) was quantified. Although their intensities were both lower in dendrites than in the soma, this gradient was steeper with RD4, leaving RD3 IR in dendrites. Dendritic arborization was abundant in RD3?/4+ pretangles, attenuated in RD3+/4+ neurons, and further attenuated in RD3+/4? ghost tangles. These findings suggest that dendritic RD4 IR retracts first, leaving RD3 IR in the dendrites. Taken together, this dendrite-oriented retraction initiates the gradual shift from RD3?/4+ pretangle neurons to RD3+/4? ghost tangles by way of RD3+/4+ NFTs. This intraneuronal profile shift may be a basis for the regional gradation featured by the similar profile shift during progression of NFT pathology.  相似文献   
72.

Background

In surgery of repair for spina bifida, various skin plastic techniques are sometimes necessary due to large skin defect or subsequent ulcers in cases when approximation on the midline is difficult.

Case report

A baby was born with a large skin defect due to huge lumbar myeloschisis and kyphosis, which was repaired 2 days after birth using Limberg’s skin flap at the peak of kyphosis. Skin ischemia around the tip of the flap gradually enlarged and resulted in a large skin ulcer. We performed negative pressure wound therapy (NPWT) using a Vacuum Assisted Closure (V.A.C.®) therapy system for 4 weeks which shrank the ulcer remarkably. Subsequently, a pedicle skin flap without graft was performed to cover the rest of the ulcer, which adapted well without CSF leakage postoperatively.

Conclusion

A combination treatment of NPWT and skin plastic surgery was successfully performed for a very young infant with spina bifida. NPWT could be another useful option for the treatment of ulcer following spina bifida repair surgery, though surgeons should carefully confirm that there is no CSF leakage before and during the procedure.  相似文献   
73.
Clinical and Experimental Nephrology - The management of congenital nephrotic syndrome of the Finnish type (CNF) is challenging. It is difficult to withdraw intravenous albumin infusions, resulting...  相似文献   
74.
75.

Background

This study aimed to evaluate the recurrence rates, timings, locations, and risk factors, and survival in patients with lymph node-negative superficial esophageal squamous cell carcinomas (ESCCs).

Methods

We investigated 167 patients with pathological T1 thoracic ESCC who underwent curative esophagectomy with lymphadenectomy between 1986 and 2013. They were classified into lymph node-negative and lymph node-positive groups, each of which included 15 relapsed patients. The recurrence rates, timings, locations, and risk factors, and survival were examined retrospectively.

Results

Significantly better recurrence (12.4 %) and the 5-year overall survival (85.7 %) rates were seen in patients with node-negative superficial ESCC compared with those with node-positive superficial ESCC. Relapsed patients with node-negative superficial ESCC showed a 5-month delay in the time to recurrence compared with relapsed patients with node-positive superficial ESCC, but the recurrence locations were similar. Upper thoracic tumors and the presence of lymph node metastases were independent risk factors for recurrence in superficial ESCC patients, but we did not determine any risk factors in patients who were node negative only. The 5-year overall survival rates did not differ between relapsed node-negative and node-positive patients. Furthermore, the mean times to death and the survival rates from recurrence to death were similar in the node-negative (20.3 months and 9.3 %, respectively) and in the node-positive patients (19.1 months and 13.6 %, respectively) who had relapsed.

Conclusions

Node-negative and node-positive superficial ESCC patients should be followed up similarly, because when recurrences occur, the prognoses and the times to death are similar in node-negative and node-positive superficial ESCC patients.
  相似文献   
76.
Kamei Y  Aoki M 《Archives of virology》2007,152(5):861-869
Summary. We screened in vitro antiviral activity against a salmonid pathogenic virus, infectious hematopoietic necrosis virus (IHNV), from the extracts of a total of 342 species of marine algae collected from the Japanese coastline. The anti-IHNV activity was found primarily in MeOH extracts, and the extract from one marine brown alga in particular, Eisenia bicyclis, showed high anti-IHNV activity. The anti-IHNV compound was isolated and purified as MC15 from the E. bicyclis extract, and the chemical structure was determined by several spectrometric analyses. The antiviral compound was proved to be a chlorophyll c2 derivative lacking the metal ion Mg2+. MC15 showed similar antiviral activity against other salmonid enveloped viruses such as Paralichthys olivaceus virus and Oncorhynchus masou virus, and stability against any pH and temperatures up to 100 °C. No cytotoxicity was observed at up to 5 μg/ml. The antiviral mechanism of MC15 appears to be direct inactivation of the viral particles. A time course study showed that the inactivation of IHNV was completed within 40 min when 200 PFU of IHNV was reacted with MC15 at 800 ng/ml.  相似文献   
77.
78.
79.
Surgery Today - We introduced a superior approach and a unique technique to retract the stomach, called the “stomach roll-up technique”, to standardize laparoscopic distal...  相似文献   
80.
A 78-year-old male presented with the chief complaints of abdominal pain and vomiting. Contrast-enhanced computed tomography and abdominal angiography showed occlusion of the superior mesenteric artery due to thrombosis, and emergency percutaneous transluminal angioplasty and stent placement were carried out. Two months later, stent thrombosis developed, and a second stent was placed. Eight months later, he complained of general fatigue and anorexia. Gastrointestinal endoscopy revealed a duodenal ulcer at the third portion close to the superior mesenteric artery. Thirteen days after conservative management, duodenal ulcer penetration into the superior mesenteric artery with subsequent air embolism developed, and the patient died of multiple organ failure.  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