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   387篇
  免费   17篇
  国内免费   1篇
儿科学   12篇
妇产科学   3篇
基础医学   63篇
口腔科学   8篇
临床医学   28篇
内科学   63篇
皮肤病学   3篇
神经病学   11篇
特种医学   61篇
外科学   23篇
综合类   15篇
预防医学   15篇
眼科学   34篇
药学   32篇
中国医学   10篇
肿瘤学   24篇
  2023年   1篇
  2022年   4篇
  2021年   2篇
  2020年   3篇
  2019年   2篇
  2018年   7篇
  2017年   4篇
  2016年   3篇
  2015年   8篇
  2014年   15篇
  2013年   27篇
  2012年   35篇
  2011年   26篇
  2010年   18篇
  2009年   16篇
  2008年   24篇
  2007年   16篇
  2006年   9篇
  2005年   17篇
  2004年   13篇
  2003年   5篇
  2002年   4篇
  2001年   4篇
  2000年   1篇
  1999年   8篇
  1998年   7篇
  1997年   15篇
  1996年   11篇
  1995年   13篇
  1994年   9篇
  1993年   14篇
  1992年   4篇
  1991年   1篇
  1990年   5篇
  1989年   8篇
  1988年   10篇
  1987年   10篇
  1986年   6篇
  1985年   3篇
  1983年   1篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1979年   1篇
  1978年   3篇
  1977年   3篇
  1976年   1篇
  1971年   1篇
  1970年   1篇
排序方式: 共有405条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
BACKGROUND: A range of allometric coefficients have been proposed in describing the maximal oxygen uptake (VO2max): body mass relation in children using weight-bearing ergometry. However, a wide deviation in the allometric coefficients for VO2max may be apparent when selected pediatric cohorts are studied in conjunction with clinical intervention for growth abnormalities. AIM: The purpose of this study was to determine the allometric coefficients for VO2max after short-term pharmacologically induced growth in pre- and early pubescent children. SUBJECTS AND METHODS: The treatment group consisted of nine subjects with non-growth hormone (GH)-deficient short stature and one with GH-deficient short stature (mean age: 13.7+/-1.7 years). Ten pre- and early pubescent children matched for age, height, weight, VO2max and body mass index (BMI) were controls. The treatment group were evaluated before (Pre-GH) and after (Post-GH) 4 months of subcutaneous GH therapy (0.05 mgkg(-1)day(-1) x 6 days week(-1)). RESULTS: The mean ontogenetic coefficient for the treatment group was 1.50+/-0.20 and for the control group was 0.77+/-0.34. The mean allometric coefficient for body mass relative to VO2max was significantly higher in the treatment group compared with the control group (p<0.05). Height, weight, fat free mass (FFM), VO2max indexed to body mass (mLkg(-1)min(-1)) and FFM (mLkgFFM(-1)min(-1)) increased (p<0.05) with GH therapy. GH therapy also increased insulin-like growth factor-I (IGF-I) and served as a biochemical marker of GH therapy (p<0.05). The control group had no significant differences in all the variables tested (p<0.05). CONCLUSION: The scaling for oxygen uptake (VO2) for body mass varies with GH treatment and the increase in VO2max that commonly occurs in conjunction with physical growth in the pre-and early pubescent individual may be linked to an increase in FFM and linear size.  相似文献   
5.
Hereditary hearing impairment affects about 1 in 1000 newborns. In most cases hearing loss is non-syndromic with no other clinical features, while in other families deafness is associated with specific clinical abnormalities. Analysis of large families with non-syndromic and syndromic deafness have been used to identify genes or gene locations that cause hearing impairment. The present report describes a large Norwegian family with autosomal dominant non-syndromic, progressive high tone hearing loss with linkage to 1q21-q23. A maximum LOD score of 7.65 (theta = 0.00) was obtained with the microsatellite marker D1S196. Analysis of recombinant individuals maps the deafness gene (DFNA7) to a 22 cM region between D1S104 and D1S466. The region contains several attractive candidate genes. This report supports the idea of extensive genetic heterogeneity in hereditary hearing impairment and represents the first localization of a deafness gene in a Norwegian family.   相似文献   
6.
Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes.  相似文献   
7.
A population based hybrid design combining element of cohort and cross-sectional approach was used to develop a simple clinical algorithm to predict individual probability of developing hypertension (systolic BP > 140 mm Hg and/or diastolic BP > 90 mmHg). 3615 soldiers initially normotensive at the time of induction into high altitude, were studied by systematic random sampling. Multiple logistic regression analysis showed a high significant association between hypertension and age, body mass index (BMI), tobacco smoking and alcohol consumption. Using the constant/coefficient values obtained from the logistic model and the receiver operating characteristics (ROC) curve analysis, the following predictive rule was developed – To the age in years, add (BMIx 3.86); also add 5.53 if he is a smoker; and add 19.81 if he consumes alcohol. If the total exceeds 142, the individual is at high risk of developing hypertension. This algorithm carries a sensitivity of 68.2% and specificity of 78.5%.KEY WORDS: Hypertension, High altitude  相似文献   
8.
9.
10.
The developments of resistance and persistence to chemical insecticides and concerns about the non-target effects have prompted the development of eco-friendly mosquito control agents. The aim of this study was to investigate the larvicidal activities of synthesized cobalt nanoparticles (Co NPs) using bio control agent, Bacillus thuringiensis against malaria vector, Anopheles subpictus and dengue vector, Aedes aegypti (Diptera: Culicidae). The synthesized Co NPs were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), Field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy, and Transmission electron microscopy (TEM). XRD analysis showed three distinct diffraction peaks at 27.03°, 31.00°, and 45.58° indexed to the planes 102, 122, and 024, respectively on the face-centered cubic cobalt acetate with an average size of 85.3 nm. FTIR spectra implicated role of the peak at 3,436 cm?1 for O–H hydroxyl group, 2924 cm?1 for methylene C–H stretch in the formation of Co NPs. FESEM analysis showed the topological and morphological appearance of NPs which were found to be spherical and oval in shape. TEM analysis showed polydispersed and clustered NPs with an average size of 84.81 nm. The maximum larvicidal mortality was observed in the cobalt acetate solution, B. thuringiensis formulation, and synthesized Co NPs against fourth instar larvae of A. subpictus and A. aegypti with LC50 values of 29.16, 8.12, 3.59 mg/L; 34.61, 6.94, and 2.87 mg/L; r 2 values of 0.986, 0.933, 0.942; 0.962, 0.957, and 0.922, respectively.  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