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   4383篇
  免费   118篇
  国内免费   15篇
耳鼻咽喉   145篇
儿科学   182篇
妇产科学   209篇
基础医学   273篇
口腔科学   241篇
临床医学   389篇
内科学   876篇
皮肤病学   107篇
神经病学   239篇
特种医学   168篇
外科学   972篇
综合类   75篇
一般理论   1篇
预防医学   143篇
眼科学   175篇
药学   177篇
中国医学   5篇
肿瘤学   139篇
  2024年   9篇
  2023年   22篇
  2022年   32篇
  2021年   76篇
  2020年   59篇
  2019年   75篇
  2018年   87篇
  2017年   66篇
  2016年   94篇
  2015年   92篇
  2014年   119篇
  2013年   165篇
  2012年   270篇
  2011年   294篇
  2010年   156篇
  2009年   139篇
  2008年   330篇
  2007年   412篇
  2006年   406篇
  2005年   388篇
  2004年   286篇
  2003年   246篇
  2002年   232篇
  2001年   118篇
  2000年   97篇
  1999年   87篇
  1998年   13篇
  1997年   17篇
  1996年   9篇
  1995年   10篇
  1994年   5篇
  1993年   4篇
  1992年   26篇
  1991年   18篇
  1990年   18篇
  1989年   4篇
  1988年   3篇
  1987年   2篇
  1986年   5篇
  1985年   4篇
  1982年   2篇
  1977年   2篇
  1974年   3篇
  1972年   2篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有4516条查询结果,搜索用时 15 毫秒
101.
BACKGROUND: Ras oncogenes are found in 25% of human tumors and they significantly affect prognosis. One of the major fields studied to improve anticancer drugs is blockade of the oncogenic ras protein function. One of the mechanisms to block the function of these proteins is to block farnesylation using a farnesyl transferase inhibitor (FTI) and thus to prevent the ras from anchoring to the cell membrane. METHODS: In this study, we investigated the effects of FTI L-744,832 either alone or in combination with 5-fluorouracil (5-FU; 1 microM/l) and radiotherapy (2, 6, and 10 Gy) on the colon cancer cell line DLD-1 with mutations in K-, N- and H-ras, c-myb, c-myc, p53, fos, sis and DNA repair genes. Drugs were added 3 h after cultivation. Radiotherapy was performed on the 3rd day of the study. On the 3rd day, medium and drugs were changed. Evaluations were performed on the 6th day. RESULTS: Administration of L-744,832, neither alone nor its combination with 5-FU and radiation, affected the number of DLD-1 cells and apoptosis rates. Regarding its effects on the cell cycle, L-744,832 was shown to lead to G(0)/G(1) and G(2)/M accumulation in a dose-dependent manner when administered alone. However, in combination with 5-FU, only a G(0)/G(1) accumulation was observed. CONCLUSION: Our study showed that FTI L-744,832 does not effect the cell number and apoptosis rate of DLD-1 cells and it cannot overcome 5-FU and radiation resistance, although it is able to modify some phases of the cell cycle.  相似文献   
102.
103.
Endocarditis caused by Stenotrophomonas maltophilia   总被引:2,自引:0,他引:2  
Stenotrophomonas maltophilia is frequently isolated from hospital environments. In recent years, it has been reported that this bacterium is causing hospital infections at increasing rates and is gaining importance because of its multiple resistance. Although it has been related to several infections, endocarditis caused by S. maltophilia is rarely encountered. In this case study, endocarditis in a 40-y-old man with a history of aortic valve replacement is presented. Blood cultures revealed S. maltophilia to be the aetiological agent, which showed multiresistance to various antibiotics. Ticarcillin-clavulanate and trimethoprim-sulfamethoxazole were used in the treatment.  相似文献   
104.
105.

Objective

Cubital tunnel syndrome (CuTS) is the second most common compression neuropathy in the arm, but the existence of a compressive cause has not been determined conclusively and the majority of the cases are idiopathic. In this paper, involvement sides of limbs of patients with cubital tunnel syndrome were studied.

Material and methods

Between October 2008 and December 2011, the clinical assessment of consecutive operated patients with cubital tunnel syndrome in Rize Education and Research Hospital were analysed. The diagnosis and severity of syndrome was based on electro-diagnostic study.

Results

This study included 57 consecutive patients with cubital tunnel syndrome (39 men, 18 women; mean age, 44,7 years; range, 23–79 years; mean age, 44,7 years; range, 23–79 years); 31 patients underwent surgical treatment. Involvement was on the right side in 18 and on the left in 39 patients. Severity scores and MCV were statistically significant between sides.

Conclusion

Profound involvement with cubital tunnel was found in left elbow. According to the finding of non-dominant elbow involvement in our study, the exact etiology and ideal management of cubital tunnel syndrome continues to be heavily debated.  相似文献   
106.
107.

Purpose

Vitamin K deficiency bleeding is one of the most common causes of acquired hemostatic disorder in early infancy. Although vitamin K is practiced routinely after every birth in Turkey, children with type of vitamin K deficiency bleedings (L-VKDB) can be encountered. We aimed to evaluate the clinical features of the children with L-VKDB reported from Turkey.

Methods

Between 1995 and 2013, 48 studies reporting 534 children with L-VKDB were evaluated in this study.

Results

Of the 534 reported children (178 girls, 356 boys), 486 (91 %) were extremely breastfed. The most common bleeding sites were intracranial hemorrhage, gastrointestinal, and umbilical in 414 (77.4 %), 33 (6.2 %), and 33 (6.2 %) children, respectively, and 35 (6.6 %) children had been diagnosed incidentally without any bleeding. The etiology of 399 (74.7 %) children were classified as idiopathic, whereas 135 (25.3 %) were secondary. Intramuscular vitamin K was administered in 248 (46.4 %), not administered in 228 (42.7 %), and the administration of vitamin K were not determined in 58 (10.9 %) children. The outcomes of Turkish cohort showed that 111 (20.8) children died, 257 (48.1 %) cases developed neurologic deficit (mainly epilepsy and psychomotor retardation), and only 166 (31.1 %) patients recovered without squeal.

Conclusions

The compliance of prophylactic measures in Turkey does not seem to be satisfactory. As a further measure of tomorrow, we vigorously emphasize that a national surveillance program may be initiated. An additional intramuscular dose or oral supplementation of vitamin K especially for exclusively breast-fed infants may reduce this catastrophic problem in our country.  相似文献   
108.
109.
Congenital megalourethra is a rare urogenital malformation characterized by severe dilatation and elongation of the penile urethra. It causes functional obstruction of the lower urinary system. Herein, we present a newborn with congenital megalourethra with single umbilical artery.  相似文献   
110.

Purpose

Tissue damage in necrotizing enterocolitis (NEC) of infants occurs as a result of an uncontrolled inflammatory response. The aim of this study was to investigate any potential anti-inflammatory effects that Etanercept may have on the inflammatory response in an experimental NEC model in newborn rats.

Methods

Newborn pups were randomized into three groups immediately after birth (Control, NEC + Placebo and NEC + Etanercept). Pups in the NEC + Placebo and NEC + Etanercept groups were subjected to an NEC-inducing protocol (hypercarbia, hypothermia and hyperoxia) twice a day for 3 days. Pups in the NEC + Etanercept group were given an intraperitoneal injection of Etanercept. Rats were harvested for biochemical and histopathological examinations.

Results

The histopathological injury score of rats in the NEC + Placebo group was significantly higher compared to the NEC + Etanercept and Control groups (p < 0.05 for both comparisons). Tissue levels of tumor necrosis factor-α, interleukin-1β, and malondialdehyde were higher in the placebo group compared to the Etanercept group.

Conclusion

Our results suggest that Etanercept attenuates intestinal tissue damage in NEC by reducing inflammation and blocking the production of free-oxygen radicals, while also reducing tissue levels of tumor necrosis factor-α and interleukin-1β.  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