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   334067篇
  免费   43045篇
  国内免费   2866篇
耳鼻咽喉   7499篇
儿科学   11183篇
妇产科学   6234篇
基础医学   28556篇
口腔科学   9445篇
临床医学   40224篇
内科学   88804篇
皮肤病学   11936篇
神经病学   30082篇
特种医学   12125篇
外国民族医学   26篇
外科学   63693篇
综合类   1863篇
现状与发展   73篇
一般理论   70篇
预防医学   25946篇
眼科学   6881篇
药学   12361篇
中国医学   776篇
肿瘤学   22201篇
  2023年   5572篇
  2022年   3005篇
  2021年   7090篇
  2020年   8519篇
  2019年   5922篇
  2018年   12482篇
  2017年   11066篇
  2016年   11893篇
  2015年   12536篇
  2014年   21158篇
  2013年   22953篇
  2012年   17222篇
  2011年   17755篇
  2010年   16492篇
  2009年   19639篇
  2008年   15417篇
  2007年   14293篇
  2006年   16028篇
  2005年   13572篇
  2004年   12277篇
  2003年   10452篇
  2002年   8576篇
  2001年   8847篇
  2000年   8066篇
  1999年   7678篇
  1998年   5332篇
  1997年   4845篇
  1996年   4734篇
  1995年   4359篇
  1994年   3089篇
  1993年   2617篇
  1992年   4147篇
  1991年   4081篇
  1990年   3481篇
  1989年   3577篇
  1988年   3198篇
  1987年   2886篇
  1986年   2770篇
  1985年   2546篇
  1984年   1899篇
  1983年   1618篇
  1982年   1184篇
  1981年   1030篇
  1980年   951篇
  1979年   1287篇
  1978年   1005篇
  1977年   951篇
  1975年   865篇
  1974年   812篇
  1973年   813篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Computed tomography angiogram of the head and neck has lately become a pivotal imaging modality in the patient with acute stroke symptoms due to its high resolution, accuracy, speed, and sensitivity in the assessment of brain parenchyma and vascular patency.  相似文献   
992.
Epidemiological data from the United States of America (USA) indicate that the incidence and mortality of prostate cancer is higher among Black African-American men (AAM) than among White (Caucasian) American men (CAM). Earlier studies suggesting that prostate cancer is relatively rare among indigenous Black men in Africa are probably flawed by underreporting because recent studies indicate that the incidence rates among Black men are similar to those of White men living in Africa. The higher incidence of prostate cancer among AAM has been ascribed to racial differences in genetic susceptibility, dietary factors, or androgen metabolism. However, it may also be due to registration artefacts because in Africa the reported incidence rates of prostate cancer in different countries correlate directly with the per capita gross national product, suggesting improved access to medical facilities is responsible for higher reported incidence rates.

The greater prostate cancer mortality among AAM may result from higher tumour grade and stage and higher serum PSA at presentation, but it has also been suggested that prostate cancer is biologically more aggressive in AAM than in CAM. However, recent studies indicate that tumour grade and stage and serum PSA at presentation are similar in the races, with no difference in survival after multivariate analysis controlling for pretreatment cancer severity. This suggests that the higher prostate cancer mortality among AAM results from socio-economic factors and limited access to healthcare. Black men living inside as well as outside of Africa still tend to present with locally advanced or metastatic prostate cancer due to lack of early detection programmes.  相似文献   

993.
Early glottic carcinoma, specifically stage I or II, can be treated with endoscopic excision, radiation therapy, or open partial laryngectomy. Over the past two decades, this topic has received intensive interest, and controversies have often focused on techniques and outcomes comparing the use of endoscopic excision versus radiation therapy. This article will discuss philosophy, techniques, and outcomes of resection using the endoscopic approach to early glottic carcinoma. Optimization through appropriate instrumentation, staging, and technical details are critical to postoperative oncologic and vocal outcomes. The reader must remember that over 90% of T1 lesions and approximately 75% of T2 lesions are curable, and therefore adherence to the principles described below is important to achieve these outcomes.  相似文献   
994.
995.
996.
BACKGROUND: Pilonidal disease is a chronic disease of the natal cleft. Recurrent follicular infection is the causative factor. Surgical treatment has a significant failure rate, and recurrence is common. Laser removal of hair in the natal cleft could be an alternative to surgery. OBJECTIVE: To determine the effectiveness of laser hair removal in the natal cleft on pilonidal disease. METHODS: Six young men with recurrent pilonidal disease were treated with laser epilation in our clinic from 2000 to 2003. Most patients had a history of one or more surgical treatments in the area, and all patients had suffered recurrent folliculitis for years. An alexandrite laser was mostly used, although, occasionally, an intense pulsed light device was used. The number of epilation treatments ranged from 3 to 11, performed at 6- to 8-week intervals. RESULTS: All patients experienced progressive resolution of the folliculitis with the laser epilation treatments. No more surgical treatments have been needed. The treatments were simple and quick, and there were no complications. CONCLUSION: Laser epilation of the natal cleft should be considered a first choice treatment for recurrent pilonidal disease. Preventive laser epilation of the natal cleft in patients with recurrent folliculitis could avoid future surgery.  相似文献   
997.
998.
Shah Geeta M.  MD    Kilmer Suzanne L.  MD 《Dermatologic surgery》2005,31(S3):1206-1210
Background:. Nonablative technologies have been used for fine lines and improvement of skin texture without significant downtime. Nonablative technologies may also be used in combination.
Objective:. To present a brief review on nonablative technologies and discuss using nonablative procedures in combination and with other adjunctive therapies.
Materials and Methods. A review of the literature was done to identify combination nonablative studies. We also discuss our own experience in combining these procedures.
Results. Various nonablative technologies can be used together, often with better outcomes and fewer treatments.
Conclusion:. Nonablative and adjunctive treatments should be performed in combination to optimize the results. Much of the information in this publication is from personal experience and expresses the opinions of these authors while citing relevant literature and studies.  相似文献   
999.
1,450 nm Long-Pulsed Diode Laser for Nonablative Skin Rejuvenation   总被引:1,自引:0,他引:1  
Doshi Seema N.  MD    Alster Tina S.  MD 《Dermatologic surgery》2005,31(S3):1223-1226
Background:. There has been growing patient demand for laser technology to treat rhytids and to refine skin texture without the associated lifestyle hindrance common to ablative cutaneous procedures. Nonablative laser systems have been developed to meet this need and, in many instances, have replaced ablative lasers as the preferred treatment modality.
Objective:. To review long-pulsed diode laser technology in the treatment of a variety of cutaneous disorders.
Materials and Methods. All publications involving 1,450 nm long-pulsed diode laser technology were reviewed and discussed.
Results. The latest generation of nonablative lasers, in the midinfrared electromagnetic spectrum, selectively targets and heats dermal tissue to stimulate collagen remodeling while sparing the epidermis.
Conclusions. Demonstrating efficacy in the treatment of a wide range of cutaneous disorders, including facial rhytids, acne vulgaris, and atrophic scars, the 1,450 nm diode laser is a useful addition to the nonablative laser armamentarium.  相似文献   
1000.
BACKGROUND: The maximum number of hair grafts that can be safely implanted in 1 cm2 is still debatable. To our knowledge, no previous report has addressed this issue in three dimensions, taking into account the size, the angle of the graft, and the intergraft distance. OBJECTIVES: To study the effect of the size and angle of the graft and the intergraft distance on dense packing. METHODS: Using a mathematical formula (the maximum number of hair grafts in 1 cm2 = 33 * cosine), the volume of the recipient area and the volume of the hair graft are calculated, assuming that the surface area of the recipient area is 1 cm2, the diameter of the hair graft is 1 mm, and the intergraft distance is 1.5 mm laterally and 1 mm anteriorly and posteriorly. RESULTS: The maximum number of hair grafts that could be implanted in 1 cm2 at a 90 angle in relation to the skin surface is 33 grafts, at a 60 angle is 28 grafts, and at a 30 angle is 16 grafts. CONCLUSION: The maximum number of hair grafts that can be implanted in any given recipient area depends on the graft size, the angle or direction of these grafts, and the intergraft distance. Where more space is allowed between the grafts, and the more acute the angle, the fewer hair grafts that can be implanted.  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