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   168342篇
  免费   32171篇
  国内免费   2487篇
耳鼻咽喉   5395篇
儿科学   5750篇
妇产科学   2778篇
基础医学   5370篇
口腔科学   2059篇
临床医学   28064篇
内科学   51686篇
皮肤病学   7799篇
神经病学   16213篇
特种医学   6752篇
外科学   43866篇
综合类   359篇
现状与发展   72篇
一般理论   8篇
预防医学   8097篇
眼科学   3907篇
药学   1896篇
  1篇
中国医学   48篇
肿瘤学   12880篇
  2024年   692篇
  2023年   4891篇
  2022年   1453篇
  2021年   3702篇
  2020年   6314篇
  2019年   2706篇
  2018年   8021篇
  2017年   7669篇
  2016年   8799篇
  2015年   8906篇
  2014年   16167篇
  2013年   16451篇
  2012年   7000篇
  2011年   7051篇
  2010年   11134篇
  2009年   14943篇
  2008年   6996篇
  2007年   5296篇
  2006年   7624篇
  2005年   4797篇
  2004年   3912篇
  2003年   2741篇
  2002年   2776篇
  2001年   3865篇
  2000年   3063篇
  1999年   3315篇
  1998年   3792篇
  1997年   3573篇
  1996年   3457篇
  1995年   3320篇
  1994年   2042篇
  1993年   1661篇
  1992年   1445篇
  1991年   1457篇
  1990年   1096篇
  1989年   1221篇
  1988年   1051篇
  1987年   885篇
  1986年   923篇
  1985年   741篇
  1984年   595篇
  1983年   561篇
  1982年   569篇
  1981年   454篇
  1980年   395篇
  1979年   335篇
  1978年   355篇
  1977年   426篇
  1975年   292篇
  1972年   312篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
It is well established that visual display unit (VDU) operators complain of visual fatigue and visual stress during after-work hours. The present study was divided into two parts. In the first part, standard eye examinations were performed on a group of VDU workers (n = 32) and a control group (n = 15); those subjects who were found to have correct vision (n = 16 and 13, respectively) participated in the second part. The eye examinations revealed that on the average, the VDU workers suffered more than twice as many visual impairments as the controls. In those with correct vision, the near point of accommodation was measured at the beginning of the workday at the start of the week, and at the end of the workday, four days later. In the VDU group, the decrease in accommodation was uniformally distributed between zero and 1.0 diopter, whereas among the non-VDU workers, 77% of the decrease was between zero and 0.25 diopter. The dynamic range of accommodation in the VDU workers on the second examination was smaller than on the first. We conclude that some of the visual stress and visual fatigue that developed at work hindered visual activities after work.  相似文献   
994.
995.
BACKGROUND: The optimal time frame to improve the quality and cosmetic appearance of scars by laser therapy has not been clearly elucidated by prior controlled clinical trials. OBJECTIVE: To determine the efficacy of the 585-nm pulsed dye laser (PDL) in the treatment of surgical scars starting on the day of suture removal. METHODS: Eleven patients (skin types I-IV) with 12 postoperative linear scars that were greater than 2 cm were treated three times on monthly intervals with the 585-nm PDL (450 micro s, 10-mm spot size, 3.5 J/cm2 with 10% overlap) on one scar half, whereas the other half received no treatment. Scars were later evaluated by a blinded examiner using the Vancouver Scar Scale (VSS) for pigmentation, vascularity, pliability, and height. Scars were then blindly examined for cosmetic appearance using a visual analog scale. RESULTS: One month after the last treatment, final scar analysis by the blinded examiner revealed a significant difference between treated and untreated sites, with the treated halves scoring better in all scar parameters in the VSS and in cosmetic appearance. The treated halves demonstrated an overall average improvement in the VSS between the first treatment score and the final score of 54% versus 10% in the controls (P=0.0002). The cosmetic appearance score (0=worst; 10=best) at final assessment was significantly better for the treated scars, scoring 7.3 versus the averaged control score of 5.2 (P=0.016). CONCLUSION: The 585-nm PDL is effective and safe in improving the quality and cosmetic appearance of surgical scars in skin types I-IV starting on the day of suture removal.  相似文献   
996.
Background: Spherophakia is an uncommon diagnosis. This is the first case report of spherophakia evaluated by ultrasound biomicroscopy.
Methods: Ultrasound biomicroscopy is a new diagnostic technique developed by one of the authors and provides images with microscopic resolution of the anterior segment. A patient with spherophakia was evaluated by ultrasound biomicroscopy (Zeiss-Humphrey, 50MHz) before and after YAG laser iridotomy.
Results: Ultrasound biomicroscopic assessment revealed a shallow anterior chamber, a very steep anterior lens curvature, iridolenticular contact, elongated zonules, and an increased distance between the lens equator and the ciliary processes. Angle closure glaucoma was due to a pupil block mechanism. The pupil block was relieved by YAG laser iridotomy.
Conclusions: Ultrasound biomicroscopy is a useful technique to confirm the diagnosis of spherophakia. The pupil block in spherophakia is relieved by YAG laser iridotomy.  相似文献   
997.
Occupational exposure to HIV is becoming a daily hazard in many emergency departments. Emergency physicians who are protected by disability insurance policies are likely to believe that if they are unable to continue working because of HIV-positive status, their disability policies will provide them with a source of income. Unfortunately, analysis of case law regarding claims under disability policies shows that the law is unlikely to consider an asymptomatic, HIV-positive physician disabled for purposes of payments under disability policies. Therefore, it is necessary for emergency physicians to make sure this issue is resolved before buying and relying on a disability policy so that an anticipated safety net will be operative over the full range of hazards that emergency physicians face.[Lavely R: The HIV-positive physician and disability insurance. Ann Emerg Med June 1994;23:1355-1362.]  相似文献   
998.
Confidentiality is a promise rooted in tradition, law andmedical ethics. Emergency physicians treat a variety of patients to whom confidentiality is of vital importance: employees, celebrities, victims of violence or disaster, minors, students, criminals, drug abusers, and patients with STDs. EDs should develop methods of ensuring confidentiality for all patients.34Although confidentiality is an important principle thatshould be respected and guarded, it is not absolute. Various laws mandate disclosure of certain patient information; in addition, an overriding moral duty may occasionally require, a breach of confidentiality. As Beauchamp and Childress noted, “the therapeutic role may sometimes have to yield to ones role as citizen and as protector of the interests of others”.19 In general, however, circumstances requiring a breach of confidentiality are rare.  相似文献   
999.
A method of electroretinogram c-wave recording in the rat was developed that uses a contact lens electrode connected through a saline bridge with a silver-silver chloride half-cell. A cluster of light-emitting diodes, regulated by an electronic light-emitting diode stimulator, was used as a light source. The method enables recordings of c-waves of 0.4–1.6 mV amplitude as well as other electroretinogram components in narrow limits of variation. The two main sources of response variability are voltage shunting and eyeball protrusion.  相似文献   
1000.
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