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   3318篇
  免费   304篇
  国内免费   22篇
耳鼻咽喉   23篇
儿科学   91篇
妇产科学   80篇
基础医学   386篇
口腔科学   235篇
临床医学   302篇
内科学   583篇
皮肤病学   70篇
神经病学   344篇
特种医学   159篇
外科学   433篇
综合类   91篇
预防医学   363篇
眼科学   104篇
药学   253篇
中国医学   2篇
肿瘤学   125篇
  2021年   44篇
  2020年   30篇
  2019年   42篇
  2018年   62篇
  2017年   50篇
  2016年   41篇
  2015年   49篇
  2014年   58篇
  2013年   86篇
  2012年   119篇
  2011年   166篇
  2010年   79篇
  2009年   92篇
  2008年   98篇
  2007年   146篇
  2006年   116篇
  2005年   128篇
  2004年   116篇
  2003年   101篇
  2002年   109篇
  2001年   73篇
  2000年   89篇
  1999年   86篇
  1998年   55篇
  1997年   61篇
  1996年   55篇
  1995年   50篇
  1994年   41篇
  1993年   36篇
  1992年   73篇
  1991年   54篇
  1990年   58篇
  1989年   78篇
  1988年   69篇
  1987年   73篇
  1986年   78篇
  1985年   77篇
  1984年   59篇
  1983年   63篇
  1982年   35篇
  1981年   40篇
  1979年   53篇
  1978年   50篇
  1977年   38篇
  1976年   42篇
  1974年   35篇
  1973年   38篇
  1971年   28篇
  1970年   32篇
  1969年   40篇
排序方式: 共有3644条查询结果,搜索用时 0 毫秒
101.
We explored how oral and maxillofacial (OMF) consultants describe themselves in their correspondence. We did a telephone survey of OMF surgeons’ secretaries and compiled data on the specialist titles used. Data were available for 290 consultants and 19 different titles were identified. A total of 190 (66%) consultants used the title OMF surgeon alone and a further 22 (8%) combined it with the name of a subspecialty. The remaining 78 (27%) used 11 alternative titles. Of those surveyed, 212 (73%) continue to use the specialty title of OMF surgeon with or without the name of a subspecialty comprising a readily identifiable group of specialists.  相似文献   
102.
A 35-year-old insulin-dependent diabetic woman presented at 8 weeks gestation with multiple severe hypoglycaemic episodes occurring during the day and night without warning. Her pre-pregnancy insulin dosage of 45 units daily was progressively reduced by 73 % to 12 units daily by week 17 because of multiple hypoglycaemic episodes. Investigation showed no pathological cause for the hypoglycaemia. Insulin dosage increased to 16 units daily by week 19 and then increased sharply to 60 units daily at 23 weeks and finally to 72 units at week 37. Following delivery her insulin dosage returned to pre-pregnancy values. Insulin-dependent diabetic women may rarely develop exaggerated insulin sensitivity in the first trimester of pregnancy resulting in severe hypoglycaemia, but spontaneous improvement occurs with increasing insulin resistance in the second and third trimesters.  相似文献   
103.
Mistakes in treatment of accident cases before reaching hospital   总被引:1,自引:0,他引:1  
B I Bodai  C B Walton  J P Smith 《Injury》1987,18(1):18-20
  相似文献   
104.
We have performed a 2-year prospective double-masked study to determine whether the bisphosphonate pamidronate can prevent bone loss in postmenopausal women and its optimal dosage regimen. One hundred and twenty-one such women (mean ± SD age 57.6±3.4 years; mean ± SD time since menopause 7.5±3.5 years) were randomized to receive either oral pamidronate (300 mg/day) for 4 weeks every 4 months (group A), oral pamidronate (150 mg/day) for 4 weeks every 2 months (group B) or identical placebo capsules (group C). Bone mineral density (BMD) measurements at the lumbar spine and proximal femur were performed at baseline and at 6-month intervals for 2 years using dual-energy X-ray absorptiometry. BMD at the lumbar spine (L2–4) increased significantly in groups A and B after 2 years of treatment (mean ± SD 2.8±2.1% and 3.0±2.9% respectively, bothp<0.001) but decreased in the placebo group (–1.6±3.1%,p<0.01). Identical results were seen for BMD at the femoral neck, which increased significantly in groups A and B after 2 years of treatment (1.2±2.3% and 1.3±2.9% respectively, bothp<0.05) but decreased in the placebo group (–1.9±3.9%,p<0.05). There were significant differences over 2 years between the groups at all anatomical sites (lumbar spine, femoral neck and trochanteric region, allp<0.001; Ward's triangle,p<0.01). However, there were no significant differences between groups A and B, suggesting that the two treatment regimens were equally effective in conserving BMD. There were, however, marked differences in tolerability between the two treatment regimens: 13 women (34%) in group A withdrew from the study because of side-effects, but only 5 women (12%) in group B, which was comparable with placebo. These data demonstrate that intermittent oral pamidronate will prevent bone loss from the lumbar spine and proximal femur of postmenopausal women, and that the more frequent but lower dose regimen is well tolerated.  相似文献   
105.
PurposeMucous fistula (MF) refeeding of proximal stoma effluent in neonates after small bowel resection can promote nutrient absorption and prevent atrophy of the unused distal bowel. This study aimed to assess the safety of this practice in neonates.MethodsA retrospective chart review of all patients admitted to the neonatal intensive care unit (NICU) between 2009 and 2015 who underwent a laparotomy with creation of an enterostomy and mucous fistula was performed. Patients were included if they were refed proximal stoma effluent into the MF.ResultsThirty-one patients were identified that were refed. There were no major complications (perforation, stricture, death) related to refeeding. Patients were refed for an average of 41 days (± 22), with patients gaining an average of 25.7 g/day (± 10.1) while being refed. Total parental nutrition (TPN) was administered for an average of 55 days (± 31.4) between resection and reanastomosis, with only 7 (23%) developing cholestasis and 15 (48%) reaching full feeds in this time. Mean time to full feeds after reanastomosis was 36 days (± 58.6) with two patients having anastomotic leaks.ConclusionMF refeeding is a safe technique that has the potential to contribute to significant weight gain and a decreased dependence on total parenteral nutrition.Level of evidenceII  相似文献   
106.
107.
108.
109.
In soccer, heading may be related to subsequent neurological impairment. Accurate measures of heading exposure are therefore important. This study evaluated whether 12 female youth players accurately recalled their average number of headers over an entire soccer season (20 games total). Their self-reported average number of headers per game was multiplied by the number of games that they participated in, and were compared to actual number of headers extracted from game video. All players overestimated the number of headers compared to game video. Linear regression analysis indicated that self-reported headers overestimated the number of headers by 51%. While self-reports are a convenient way to estimate heading behaviour, they do not accurately represent the number of headers that players perform. Self-reports of heading exposure should be interpreted with caution.  相似文献   
110.
To better understand the role of growth hormone in regulating fish growth, the cDNA of growth hormone receptor (GHR) was cloned from the liver of masu salmon (Oncorhynchus masou) and characterized. The masu salmon GHR (msGHR) sequence revealed common features of a GHR, including a (Y/F)GEFS motif in the extracellular domain, a single transmembrane region, and Box 1 and Box 2 in the intracellular domain. However, the amino acid sequence identity was low (49%) compared to GHRs of other vertebrates including seven teleosts, and the putative msGHR protein lacked one pair of cysteine residues in the extracellular domain. To verify the identity of the msGHR, the recombinant protein of the extracellular domain was expressed with a histidine tag protein (His-msGHR-ECD), refolded and purified for analysis of its ligand specificity. In competition experiments, the specific binding between His-msGHR-ECD and radioiodine-labeled salmon GH was displaced completely by only salmon GH, and not by salmon prolactin or somatolactin. A real-time RT-PCR assay was used to measure salmon GHR mRNA in the liver of fed and fasted coho salmon (Oncorhynchus kisutch). The levels of hepatic GHR mRNA were lower in fasted fish compared to fed fish after 3 weeks, suggesting that GHR gene expression is reduced following a long-term fast. These results confirm the identity of the salmon GHR based on ligand specificity and response to fasting.  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