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   2287篇
  免费   220篇
  国内免费   9篇
耳鼻咽喉   10篇
儿科学   69篇
妇产科学   109篇
基础医学   393篇
口腔科学   110篇
临床医学   208篇
内科学   357篇
皮肤病学   30篇
神经病学   124篇
特种医学   372篇
外科学   218篇
综合类   36篇
一般理论   1篇
预防医学   167篇
眼科学   79篇
药学   151篇
肿瘤学   82篇
  2021年   43篇
  2020年   19篇
  2019年   27篇
  2018年   33篇
  2017年   20篇
  2016年   19篇
  2015年   24篇
  2014年   33篇
  2013年   71篇
  2012年   73篇
  2011年   79篇
  2010年   55篇
  2009年   39篇
  2008年   77篇
  2007年   92篇
  2006年   101篇
  2005年   101篇
  2004年   106篇
  2003年   59篇
  2002年   75篇
  2001年   76篇
  2000年   73篇
  1999年   69篇
  1998年   39篇
  1997年   37篇
  1996年   36篇
  1995年   31篇
  1994年   35篇
  1993年   35篇
  1992年   45篇
  1991年   63篇
  1990年   56篇
  1989年   82篇
  1988年   69篇
  1987年   70篇
  1986年   57篇
  1985年   53篇
  1984年   42篇
  1983年   33篇
  1982年   29篇
  1981年   31篇
  1980年   21篇
  1979年   20篇
  1978年   31篇
  1977年   18篇
  1976年   25篇
  1975年   16篇
  1971年   21篇
  1970年   16篇
  1969年   17篇
排序方式: 共有2516条查询结果,搜索用时 390 毫秒
31.
32.
Schistosoma mansoni-infected wild-type (WT) mice develop a Th2 response and chronic disease. In contrast, infected interleukin-4 double-deficient (IL-4(-/-)) mice develop a Th1-like response and an acute, lethal syndrome. Disease severity in these animals correlates with excessive and prolonged production of nitric oxide (NO) associated with enhanced antigen-driven gamma interferon (IFN-gamma) production in the absence of IL-4. Strikingly, splenic lymphocytes from infected IL-4(-/-) mice failed to proliferate as well as those from infected WT mice following stimulation in vitro with antigen or anti-CD3 antibody. Contrary to antigen-driven IFN-gamma responses, anti-CD3 antibody stimulation of splenocytes resulted in significantly less IFN-gamma being produced by CD8 cells from infected IL-4(-/-) mice than by those from infected WT mice or normal mice. NO is largely responsible for the impaired T-cell functions in infected IL-4(-/-) mice, as inhibition of iNOS significantly enhanced proliferation and IFN-gamma production.  相似文献   
33.
34.
Journal of Digital Imaging - Measurement of angles on foot radiographs is an important step in the evaluation of malalignment. The objective is to develop a CNN model to measure angles on...  相似文献   
35.

Abstract

The Floating-Harbor syndrome is a growth retardation syndrome with delayed bone age, speech development, and typical facial features. The face is triangular with deep-set eyes, long eyelashes, bulbous nose, wide columella, short philtrum, and thin lips. We present an additional patient and review 16 cases from the literature. The possible phenotype in the patient's mother suggests a dominant mode of inheritance for the syndrome.

Conclusion

The Floating Harbor syndrome is a growth deficiency syndrome characterized by proportionate short stature, characteristic face and delayed speech development. Inheritance is possibly autosomal dominant.  相似文献   
36.
The purpose of this study was to compare the diagnostic accuracy of fluorine-18 fluorodeoxyglucose (FDG) images obtained with (a) a dual-head coincidence gamma camera (DHC) equipped with 5/8-inch-thick NaI(Tl) crystals and parallel slit collimators and (b) a dedicated positron emission tomograph (PET) in a series of 28 patients with known or suspected malignancies. Twenty-eight patients with known or suspected malignancies underwent whole-body FDG PET imaging (Siemens, ECAT 933) after injection of approximately 10 mCi of 18F-FDG. FDG DHC images were then acquired for 30 min over the regions of interest using a dual-head gamma camera (VariCam, Elscint). The images were reconstructed in the normal mode, using photopeak/photopeak, photopeak/Compton, and Compton/photopeak coincidence events. FDG PET imaging found 45 lesions ranging in size from 1 cm to 7 cm in 28 patients. FDG DHC imaging detected 35/45 (78%) of these lesions. Among the ten lesions not seen with FDG DHC imaging, eight were less than 1.5 cm in size, and two were located centrally within the abdomen suffering from marked attenuation effects. The lesions were classified into three categories: thorax (n=24), liver (n=12), and extrahepatic abdominal (n=9). FDG DHC imaging identified 100% of lesions above 1.5 cm in the thorax group and 78% of those below 1.5 cm, for an overall total of 83%. FDG DHC imaging identified 100% of lesions above 1.5 cm, in the liver and 43% of lesions below 1.5 cm, for an overall total of 67%. FDG DHC imaging identified 78% of lesions above 1.5 cm in the extrahepatic abdominal group. There were no lesions below 1.5 cm in this group. FDG coincidence imaging using a dual-head gamma camera detected 90% of lesions greater than 1.5 cm. These data suggest that DHC imaging can be used clinically in well-defined diagnostic situations to differentiate benign from malignant lesions.  相似文献   
37.
Inhaled insulin     
Inhalation of regular insulin for meal time glucose control has been found to be safe, efficacious and reliable in Type I and Type II diabetics. The administration of regular insulin through the human lungs by inhalation has been conducted in at least 14 short studies in both normal and diabetic subjects beginning as early as 1925. In all studies, significant insulin absorption and lowering of blood glucose was observed in the absence of penetration enhancers. Although a concern of variable dosing was raised in early studies, the development of new reproducible delivery systems has ensured that the variability of aerosol insulin can be as good, if not better, than subcutaneous (SC) injection. In the longest controlled studies in humans to date, both Type I and Type II insulin-dependent diabetics used a novel inhaled dry powder insulin delivery system for 3 months for meal time glucose control. The study results indicate that inhaled insulin provides equivalent glucose control, measured by hemoglobin A1c, when directly compared to SC injection. Interim results from an additional study with Type II diabetics who were failing oral hypoglycemic agents suggest that adjunctive therapy with inhaled insulin markedly improved glycemic control with a low risk of hypoglycemia. In all the 3 month studies the system was efficacious, well tolerated, well liked, and resulted in reproducible results. A potential advantage of aerosol insulin is that it is more rapidly absorbed (serum peak at 5-60 min) and cleared than SC injection (peak at 60-150 min), which provides a more relevant and convenient therapy for meal time glucose control. The relative efficiency of insulin delivery by aerosol, compared to SC injection, has been estimated from the dose measured at the exit point of the aerosol device, and found to range between 8 and 25% of SC, depending on the study.  相似文献   
38.
The vasa vasorum and angioplasty   总被引:2,自引:0,他引:2  
Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.  相似文献   
39.
Information on establishing the organizational structure of sports medicine clinics is useful to clinicians intending to start or expand a clinic. The purpose of this study was to identify an organizational model of existing sports medicine facilities in terms of: 1) administration and management, 2) staff qualifications and professional development, 3) location of facility, 4) range of services, 5) availability of services, 6) physician referral base, and 7) fee structure. A survey of 250 sports medicine clinics located in or near urban cities across the United States was conducted by mail. Results of this study indicate that the typical sports medicine facility is corporate-owned. A physical therapist and/or a physician establishes policy, and the physical therapist directs day-to-day operations. On average, the professional staff have four years of athletic team affiliation and seven years of clinical experience with athletes. The staff have attended less than an average of one continuing education course a year over the last five years. The typical facility is located within five miles of a major city, within 10 miles of its primary referral source and competition, and within 10 miles of its clients' homes. Most facilities employ combinations of full-time and part-time physicians, physical therapists, and athletic trainers. The typical sports medicine facility is open 12 hours each weekday. The physician referral base is composed primarily of orthopaedic and family practice physicians who refer an average of 14 new patients a week. J Orthop Sports Phys Ther 1992;15(2):80-86.  相似文献   
40.
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