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   3582篇
  免费   259篇
  国内免费   9篇
耳鼻咽喉   28篇
儿科学   177篇
妇产科学   54篇
基础医学   564篇
口腔科学   36篇
临床医学   369篇
内科学   767篇
皮肤病学   52篇
神经病学   428篇
特种医学   223篇
外国民族医学   10篇
外科学   369篇
综合类   24篇
一般理论   1篇
预防医学   305篇
眼科学   40篇
药学   173篇
  2篇
中国医学   1篇
肿瘤学   227篇
  2021年   43篇
  2020年   24篇
  2019年   50篇
  2018年   89篇
  2017年   52篇
  2016年   63篇
  2015年   71篇
  2014年   95篇
  2013年   114篇
  2012年   175篇
  2011年   147篇
  2010年   119篇
  2009年   118篇
  2008年   152篇
  2007年   174篇
  2006年   153篇
  2005年   134篇
  2004年   126篇
  2003年   124篇
  2002年   107篇
  2001年   111篇
  2000年   95篇
  1999年   115篇
  1998年   56篇
  1997年   48篇
  1996年   40篇
  1995年   39篇
  1994年   41篇
  1993年   34篇
  1992年   69篇
  1991年   74篇
  1990年   85篇
  1989年   83篇
  1988年   76篇
  1987年   48篇
  1986年   66篇
  1985年   65篇
  1984年   57篇
  1983年   62篇
  1982年   40篇
  1981年   20篇
  1979年   44篇
  1978年   35篇
  1977年   30篇
  1976年   25篇
  1975年   30篇
  1974年   25篇
  1972年   23篇
  1971年   19篇
  1970年   22篇
排序方式: 共有3850条查询结果,搜索用时 15 毫秒
41.
42.
43.
Cross sectional studies have reported impaired growth in children with atopic dermatitis. If this growth impairment is irreversible, it would be expected to adversely influence final height attainment. The standing heights and other anthropometric parameters were assessed in 35 adults with onset of atopic dermatitis before 5 years of age and a control group of 35 adults with adult onset contact dermatitis or psoriasis. There was no significant difference in the standing height SD score, mid-parental height SD score, sitting height SD score, subischial leg length SD score, nor body mass index between the atopic dermatitis and control groups. The standing height SD score was not significantly different among: (a) patients with atopic dermatitis affecting less than 50% of their body surface area and those with greater than 50% affected; (b) patients using the four different potency topical corticosteroids; and (c) patients with atopic dermatitis without asthma and those with coexisting asthma. It is concluded that short stature is not a feature of our group of adult patients with onset of atopic dermatitis before 5 years of age, continuing into adulthood, and severe enough to require specialist care. This suggests that if growth impairment occurs in childhood, it is likely to be temporary and reversible.  相似文献   
44.
A low (L) and high-fibre (H) diet were fed to six multiparous sows during gestation in a 2 x 2 repeated Latin square design. A single meal per day was given that provided 37.2 MJ digestible energy/d. The kinetics of heat production (HP) and its partitioning (fasting HP, activity HP, and thermic effect of feeding (TEF)) were determined. The TEF was partitioned between a dynamic component (TEFst) and a constant component (TEFlt). Digestibility of energy and nutrients was lower for the diet H. In spite of the lower metabolisable energy (ME) intake (33.9 v. 35.4 MJ/d for diets H and L respectively), HP was higher for diet H (30.5 v. 28.9 MJ/d) resulting in a lower energy retention. The estimated fasting HP was 270 kJ/kg body weight 0.75 per d at day 0 of gestation and increased with advancement of pregnancy. The TEFlt was not significantly different from zero for diet L, but represented 4.1% of ME intake for diet H. The TEFst was not affected by the diet but diet H delayed the postprandial peak of HP. Total TEF was higher for diet H than for diet L (11.7 v. 8.2% of ME intake). The longer duration of eating with diet H was compensated for by less physical activity between meals, so that activity HP was equivalent for both diets. The activity HP represented 20% of ME intake but was variable between sows. The ME requirements for maintenance averaged 440 kJ/kg body weight 0.75 per d. Feeding high-fibre diets increases HP, delays the postprandial peak of HP and maintains the basal HP at a higher level.  相似文献   
45.
46.
Economic Burden of Patients with Anemia in Selected Diseases   总被引:1,自引:0,他引:1  
William B. Ershler  MD    Kristina Chen  PharmD  MS    Eileen B. Reyes    Robert Dubois  MD  PhD 《Value in health》2005,8(6):629-638
  相似文献   
47.
48.
3 cases of direct foreign body footplate trauma are described in children. A surgical exploration was decided on history, cochleovestibular signs and/or CT abnormalities. Hearing improved in all cases after surgery.  相似文献   
49.
The chemical reduction process of graphene oxide combined with a mild and controllable thermal treatment under vacuum at 200 °C for 4 hours provided a cost-effective, scalable, and high-yield route for Reduced Graphene Oxide (RGO) industrial production and became a potential candidate for producing electromagnetic interference (EMI) shielding. We investigated graphite, and RGO using l-ascorbic acid and Sodium borohydride before and after thermal treatment by carefully evaluating the chemical and morphological structures. The thermally treated l-ascorbic Acid reduction route (TCRGOL) conductivity was 2.14 × 103 S m−1 and total shielding efficiency (SET) based on mass loadings per area of shielding was 94 dB with about one-tenth less graphite weight and surpassing other graphene reduction mechanisms in the frequency range of 8.2–12.4 GHz, i.e., X-band, at room temperature while being tested using the waveguide line technique. The developed treatment represents valuable progress in the path to chemical reduction using a safe reducing agent and offering superior quality RGO rarely achieved with the top-down technique, providing a high EMI shielding performance.

The developed two-step protocol offers a superior reduced graphene oxide TCRGOL quality (7 layers), and its SET was 94 dB over the X-band.  相似文献   
50.
SignificanceLine-field confocal optical coherence tomography (LC-OCT) is a recently introduced high-resolution imaging modality based on a combination of low-coherence optical interferometry and reflectance confocal optical microscopy with line illumination and line detection. Capable of producing three-dimensional (3D) images of the skin with cellular resolution, in vivo, LC-OCT has been mainly applied in dermatology and dermo-cosmetology. The LC-OCT devices capable of acquiring 3D images reported so far are based on a Linnik interferometer using two identical microscope objectives. In this configuration, LC-OCT cannot be designed to be a very compact and light device, and the image acquisition speed is limited.AimThe objective of this work was to develop a more compact and lighter LC-OCT device that is capable of acquiring images faster without significant degradation of the resolution and with optimized detection sensitivity.ApproachWe developed an LC-OCT device based on a Mirau interferometer using a single objective. Dynamic adjustment of the camera frequency during the depth scan is implemented, using a faster camera and a more powerful light source. The reflectivity of the beam-splitter in the Mirau interferometer was optimized to maximize the detection sensitivity. A galvanometer scanner was incorporated into the device for scanning the illumination line laterally. A stack of adjacent B-scans, constituting a 3D image, can thus be acquired.ResultsThe device is able to acquire and display B-scans at 17 fps. 3D images with a quasi-isotropic resolution of 1.5  μm (1.3, 1.9, and 1.1  μm in the x,y, and z directions, respectively) over a field of 940  μm×600  μm×350  μm (x×y×z) can be obtained. 3D imaging of human skin at cellular resolution, in vivo, is reported.ConclusionsThe acquisition rate of the B-scans, at 17 fps, is unprecedented in LC-OCT. Compared with the conventional LC-OCT devices based on a Linnik interferometer, the reported Mirau-based LC-OCT device can acquire B-scans 2 times faster. With potential advantages in terms of compactness and weight, a Mirau-based device could easily be integrated into a smaller and lighter handheld probe for use by dermatologists in their daily medical practice.  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