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   41718篇
  免费   6892篇
  国内免费   346篇
耳鼻咽喉   1374篇
儿科学   2130篇
妇产科学   1452篇
基础医学   1733篇
口腔科学   3823篇
临床医学   5882篇
内科学   8555篇
皮肤病学   968篇
神经病学   3283篇
特种医学   1832篇
外国民族医学   1篇
外科学   8104篇
综合类   601篇
现状与发展   12篇
一般理论   10篇
预防医学   3376篇
眼科学   984篇
药学   1357篇
  5篇
中国医学   171篇
肿瘤学   3303篇
  2024年   245篇
  2023年   1416篇
  2022年   635篇
  2021年   1155篇
  2020年   1633篇
  2019年   953篇
  2018年   2221篇
  2017年   2012篇
  2016年   2386篇
  2015年   2282篇
  2014年   3011篇
  2013年   3735篇
  2012年   2116篇
  2011年   2277篇
  2010年   2363篇
  2009年   2542篇
  2008年   1785篇
  2007年   1590篇
  2006年   1753篇
  2005年   1508篇
  2004年   1321篇
  2003年   1217篇
  2002年   1173篇
  2001年   952篇
  2000年   883篇
  1999年   807篇
  1998年   657篇
  1997年   611篇
  1996年   646篇
  1995年   439篇
  1994年   353篇
  1993年   295篇
  1992年   214篇
  1991年   192篇
  1990年   171篇
  1989年   166篇
  1988年   142篇
  1987年   143篇
  1986年   110篇
  1985年   98篇
  1984年   89篇
  1983年   102篇
  1982年   89篇
  1981年   75篇
  1980年   48篇
  1979年   41篇
  1978年   40篇
  1977年   47篇
  1976年   34篇
  1975年   33篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
81.
Taking occlusal photographs can be challenging; they are by far the most difficult images to obtain. Achieving an ideal photograph of every arch may not always be possible. In patients with limited range of motion of the mandible, an oversized or hyperactive tongue, an excessive gag reflex, or reduced flexibility of lips and checks, the goal of an ideal occlusal photograph may not be achieved. Nevertheless, patience, practice, and attention to detail can often provide a satisfactory result.  相似文献   
82.
This report describes the outcomes of 28 children who had severe head injuries between 13–18 years of age. All were unconscious at least 24 hours and have been followed at least 2 years after injury. At present, their ages range from 18 to 27 years. Their educational achievements, social activities, marital status, functional independence, and employment at follow-up are described.  相似文献   
83.
Can nurses practice caring within a healthcare system that promotes codependency? Caring promotes mutual empowerment of all participants while codependent caring disempowers. Nurses are expected to practice caring with clients, The authors contend, however, that nursing, as historically and currently practiced within bureaucratic/patriarchal organizations, is founded on a vlue system that fosters codependency. Until nursing is practiced within the context of caring organizations and a caring healthcare system, nurses will continue to be powerless to shape their own practice as carers and burnout will continue to be a problem.  相似文献   
84.
Summary A method of dermaplaning for acne scarring using a skin graft knife is described. This surgical technique cannot be considered as a form of dermabrasion. Its advantages are reported.  相似文献   
85.
Cutaneous metastasis of vaginal carcinoma is extremely rare. So far, the total number of reported skin metastasis of vaginal carcinoma is only one. We present another case with an unusual manifestation of vagina carcinoma metastasis: skin metastasis presenting as a leg ulcer on the lower leg.  相似文献   
86.
Hypertrophic scars (HS) are a consequence of abnormal wound healing. We examined fatty acids that are contained within, and participate in, every reaction through the membrane; then, we analyzed the percentage composition of the fatty acids in deepithelialized normal dermis (ND) and HS. In vivo HS samples were obtained from six patients undergoing surgical excision, and ND samples from five patients undergoing skin grafting surgery for excess. In vitro, cultured fibroblasts from HS and ND were also analyzed. The percentage composition of fatty acids extracted from all the samples was analyzed. In vivo, arachidonic acid (20:4) was significantly more abundant in HS than in ND, in the phospholipids from both whole tissue and cell membranes. In vitro, there were no significant differences among ND, HS, and 10% fetal calf serum. The results suggest that HS formation does not necessarily involve simple excess of 20:4; however, there are considerable differences in the percentage composition of 20:4 between ND and HS. Arachidonic acid probably participates in the formation and maintenance of HS, whereas in vitro cultured fibroblasts are affected largely by fetal calf serum.  相似文献   
87.
88.
The popularity of vital tooth whitening has increased significantly over the past two decades. Professionally supervised "in-office" and "at-home" tooth whitening methods have been documented in the literature with evidence of safety and effectiveness. Although the literature includes considerable information about vital tooth whitening in adults, minimal information is available concerning vital tooth whitening in children and adolescents.
The need to provide vital tooth whitening for children might be infrequent owing to the natural whiteness of children's teeth. However, there are circumstances when tooth whitening can be desirable for children, such as fluorosis discoloration, generalized tooth darkening, post-traumatic injury discoloration, and postorthodontic tooth discoloration.
Few well-controlled clinical trials evaluating the safety and effectiveness of vital tooth whitening in children are available in the literature, Furthermore, these published clinical trials were carried out by the same principal investigator. This review examines these trials and offers recommendations accordingly.  相似文献   
89.
Keloid formation has been linked to aberrant fibroblast activity, exacerbated by growth factors and inflammatory mediators. Prostaglandin E2 (PGE2), synthesized from arachidonic acid by cyclooxygenases (COX) and synthases (PGES), acts as both an inflammatory mediator and fibroblast modulator. Although PGE2 has known antifibrotic effects in the lower airway, its role in dermal fibrosis in general, and keloid formation in particular, remains unclear. This study focused on: (1) the effects of PGE2 on keloid fibroblast migration, contraction, and collagen synthesis and (2) endogenous PGE2 synthesis in response interleukin-1beta. PGE2 decreased keloid fibroblast migration and contraction via an EP2/EP4-cAMP mechanism that disrupted actin cytoskeletal dynamics and reversed transforming growth factor-beta1-induced collagen I and III synthesis. Impaired fibroblast PGE2 production has been linked to lower airway fibrosis and recently to keloid formation. Here, we showed that interleukin-1beta stimulation leads to nuclear factor-kappaB translocation to the nucleus, resulting in up-regulation of COX-2 and microsomal PGE2 synthase 1. Up-regulation of COX-2 in, and secretion of PGE2 by keloid fibroblasts are diminished compared with their normal fibroblast counterparts. We suggest that the antifibrotic effects of PGE2 during keloid formation are potentially diminished due to aberrant paracrine fibroblast signaling. Exogenous PGE2 may supplement decreased endogenous levels and inhibit keloid formation or progression.  相似文献   
90.
BACKGROUND: Patients with primary axillary hyperhidrosis experience substantial functional impairment and reduced health-related quality of life (HRQOL). Few studies have comprehensively evaluated the effects of botulinum toxin type A (BoNT-A) on these symptoms. OBJECTIVE: To prospectively assess the effects of BoNT-A on functional impairment associated with primary axillary hyperhidrosis. METHODS: Patients treated with BoNT-A 50 U per axilla at baseline were assessed 4 and 12 weeks later. Outcome measures included functional impairment as assessed by the Hyperhidrosis Disease Severity Scale and the Hyperhidrosis Impact Questionnaire and dermatology-specific HRQOL as assessed by the Dermatology Life Quality Index. RESULTS: At weeks 4 and 12 after BoNT-A treatment, 85% and 90% of patients achieved the a priori definition of treatment responder. Patients reported less occupational and emotional impairment, spent less time managing their hyperhidrosis, and had fewer difficulties in social situations. Adverse events were uncommon (5.5%), were mild, and did not require treatment. At study end, 53% of patients reported no dermatology-specific HRQOL impairment and 90% were satisfied with treatment. CONCLUSIONS: Significant, meaningful, rapid, and durable reductions in disease severity and functional impairment, as well as improvements in HRQOL, were seen following BoNT-A treatment. BoNT-A was safe and well tolerated, producing high levels of patient satisfaction.  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