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   3914篇
  免费   778篇
  国内免费   56篇
耳鼻咽喉   96篇
儿科学   182篇
妇产科学   106篇
基础医学   249篇
口腔科学   70篇
临床医学   485篇
内科学   1013篇
皮肤病学   119篇
神经病学   241篇
特种医学   103篇
外国民族医学   1篇
外科学   1155篇
综合类   84篇
一般理论   1篇
预防医学   258篇
眼科学   163篇
药学   150篇
中国医学   4篇
肿瘤学   268篇
  2024年   19篇
  2023年   223篇
  2022年   99篇
  2021年   209篇
  2020年   171篇
  2019年   127篇
  2018年   274篇
  2017年   244篇
  2016年   226篇
  2015年   203篇
  2014年   260篇
  2013年   291篇
  2012年   192篇
  2011年   232篇
  2010年   234篇
  2009年   252篇
  2008年   155篇
  2007年   128篇
  2006年   145篇
  2005年   115篇
  2004年   104篇
  2003年   94篇
  2002年   90篇
  2001年   68篇
  2000年   30篇
  1999年   59篇
  1998年   44篇
  1997年   35篇
  1996年   38篇
  1995年   35篇
  1994年   20篇
  1993年   20篇
  1992年   31篇
  1991年   28篇
  1990年   25篇
  1989年   19篇
  1988年   14篇
  1987年   21篇
  1986年   21篇
  1985年   17篇
  1984年   9篇
  1983年   8篇
  1981年   10篇
  1980年   11篇
  1979年   11篇
  1977年   9篇
  1976年   8篇
  1975年   9篇
  1974年   9篇
  1973年   8篇
排序方式: 共有4748条查询结果,搜索用时 0 毫秒
41.
42.
43.
PURPOSE: Multiple chromosome abnormalities, including gain of chromosome20q, have been detected frequently in human pancreatic cancers. Overexpression of the STK15/BTAK/Aurora A gene located on chromosome 20q13, which encodes a centrosome-associated serine/threonine kinase, has been shown to induce chromosomal instability, leading to aneuploidy and cell transformation in multiple in vitro experimental systems. The purpose of this study was to investigate the expression and copy number alteration of STK15 in pancreatic cancer. EXPERIMENTAL DESIGN: STK15 expression at both the mRNA and protein levels together with the copy number of STK15 gene was measured in nine pancreatic carcinoma cell lines: (a) HPAF-II; (b) Aspc-1; (c) Panc-1; (d) Panc-3; (e) Panc-28; (f) Panc-48; (g) HS766T; (h) MIAPaCa-2; and (i) BxPc3. STK15 protein expression was also examined in normal pancreatic tissues and tumors by Western blotting and immunohistochemistry. RESULTS: STK15 was overexpressed in all of the nine cell lines examined, but gene amplification was infrequent. Western Blot analysis of primary tumor tissues revealed 2-10 times overexpression of STK15 protein compared with normal adjacent tissues from pancreatic cancer patients. Concurrent overexpression of cdc20, an STK15-associated protein, and reduced expression of cdc25, a mitosis-activating protein phosphatase, were detected in the same tumor samples. Elevated STK15 protein expression was detected in 22 of 38 tumor sections (58%) from pancreatic cancer patients. The extent of STK15 expression was not significantly correlated with the size, degree of differentiation, and metastasis status of the tumors. CONCLUSIONS: These results show that STK15 is overexpressed in pancreatic tumors and carcinoma cell lines and suggest that overexpression of STK15 may play a role in pancreatic carcinogenesis.  相似文献   
44.
Blue nevi are common skin neoplasms that typically present as asymptomatic solitary papules, although they may rarely occur in an agminated configuration. We describe a case of agminated blue nevus in a segmental facial distribution associated with soft tissue hypertrophy and hypertrichosis in a 16‐year‐old boy and present a review of the literature. Although they are generally considered to be benign, concurrent soft tissue changes occurring within an agminated blue nevus should be investigated thoroughly to exclude alternate diagnoses.  相似文献   
45.
46.
47.
48.
49.
The objectives of this work were (i) to characterize the pharmacokinetics of cefazolin in pregnant women undergoing elective cesarean delivery and in their neonates; (ii) to assess cefazolin transplacental transmission; (iii) to evaluate the dosing and timing of preoperative, prophylactic administration of cefazolin to pregnant women; and (iv) to investigate the impact of maternal dosing on therapeutic duration and exposure in newborns. Twenty women received 1 g of cefazolin preoperatively. Plasma concentrations of total cefazolin were analyzed from maternal blood samples taken before, during, and after delivery; umbilical cord blood samples obtained at delivery; and neonatal blood samples collected 24 h after birth. The distribution volume of cefazolin was 9.44 liters/h. The values for pre- and postdelivery clearance were 7.18 and 4.12 liters/h, respectively. Computer simulations revealed that the probability of maintaining free cefazolin concentrations in plasma above 8 mg/liter during scheduled caesarean surgery was <50% in the cord blood when cefazolin was administered in doses of <2 g or when it was administered <1 h before delivery. Therapeutic concentrations of cefazolin persisted in neonates >5 h after birth. Cefazolin clearance increases during pregnancy, and larger doses are recommended for surgical prophylaxis in pregnant women to obtain the same antibacterial effect as in nonpregnant patients. Cefazolin has a longer half-life in neonates than in adults. Maternal administration of up to 2 g of cefazolin is effective and produces exposure within clinically approved limits in neonates.  相似文献   
50.
Surgical drains are commonly used in plastic surgery. Drains are subsequently removed at arbitrary volumes depending on local protocols. The rational for when to remove a drain has not been scientifically determined. We compared removal of drains at ≤30?ml/24?h vs. ≤50?ml/24?h for 158 wounds, in 90 patients. Postoperative complications, length of hospital stay and resulting cost–benefit were considered. Prospective data were collected for two consecutive similar cohorts of patients undergoing abdominoplasty, bilateral breast reduction and breast augmentation. In the first cohort, drains were removed when drainage was ≤30?ml/24?h and the second cohort when ≤50?ml/24?h. Demographics, days of drainage, surgeon grade and duration of postoperative hospital stay were recorded. Patient records were then analysed and complications recorded, including haematoma, infection, seroma, wound breakdown and fat necrosis. The median postoperative stay for all three operations for both drainage cohorts was similar with no statistically significant difference; however, the drainage time in breast augmentation was significantly less in the <50?ml/24?h group. There were no significant differences in outcome measures between the patients undergoing abdominoplasty, breast reduction or breast augmentation. Drain removal at ≤50 vs. ≤30?ml/24?h did not result in an increase in postoperative morbidity or adverse outcome in any of the three different operation types.  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