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   1387945篇
  免费   120064篇
  国内免费   10070篇
耳鼻咽喉   17194篇
儿科学   43443篇
妇产科学   37026篇
基础医学   188898篇
口腔科学   37032篇
临床医学   127354篇
内科学   285496篇
皮肤病学   32257篇
神经病学   112989篇
特种医学   57561篇
外国民族医学   296篇
外科学   215992篇
综合类   42036篇
现状与发展   8篇
一般理论   418篇
预防医学   110593篇
眼科学   29516篇
药学   99368篇
  67篇
中国医学   5815篇
肿瘤学   74720篇
  2021年   11617篇
  2018年   15315篇
  2017年   12414篇
  2016年   14558篇
  2015年   16924篇
  2014年   23193篇
  2013年   32837篇
  2012年   40915篇
  2011年   43690篇
  2010年   27793篇
  2009年   26614篇
  2008年   39312篇
  2007年   41661篇
  2006年   42538篇
  2005年   40864篇
  2004年   38233篇
  2003年   37158篇
  2002年   34902篇
  2001年   66844篇
  2000年   68589篇
  1999年   57304篇
  1998年   17151篇
  1997年   15446篇
  1996年   16367篇
  1995年   16528篇
  1994年   15359篇
  1993年   14308篇
  1992年   47252篇
  1991年   45882篇
  1990年   44104篇
  1989年   41913篇
  1988年   38849篇
  1987年   38164篇
  1986年   35931篇
  1985年   34689篇
  1984年   26397篇
  1983年   22133篇
  1982年   13859篇
  1981年   12461篇
  1980年   11726篇
  1979年   23558篇
  1978年   17086篇
  1977年   14388篇
  1976年   13185篇
  1975年   13730篇
  1974年   16102篇
  1973年   15404篇
  1972年   14180篇
  1971年   13038篇
  1970年   11887篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Surgical treatment of acoustic neuroma has been reviewed in the medical literature, but assessment of outcome from the patient's perspective has received little attention. The Acoustic Neuroma Association (A.N.A.) is a large organization of acoustic neuroma patients which provides information and support services. This article reports the subjective assessment of symptoms, diagnosis, treatment, and outcome as evaluated by 541 A.N.A. members. This retrospective study presents an extensive overview of the experience of acoustic neuroma patients treated at a variety of institutions, and provides a unique perspective not previously represented in the medical literature.  相似文献   
992.
Immunologic and pharmacologic concepts of monoclonal antibodies   总被引:2,自引:0,他引:2  
While monoclonal antibodies have solved many of the difficulties of using immunologic reagents for radioimmunodiagnosis and therapy, in the 13 years since their introduction a number of persistent problems remain, most notably a low yield of antibody-producing cells from the fusion process, difficulty in obtaining high-affinity antibodies, and the potential immunogenicity of murine immunoglobulins (Igs). Several solutions are under development, including fusion techniques that enrich for cells producing desired antibodies, production of human-mouse chimeric antibodies by recombinant DNA technology, and the generation of human monoclonal antibodies by promising new approaches. Until these upcoming methodologies are established, and to better direct their development and application, a sound understanding of the pharmacology of presently available native and modified monoclonal antibodies is crucial. Although much has been already determined in this area, a great deal of further clarification remains necessary.  相似文献   
993.
D C Perry  L M Grimes 《Brain research》1989,477(1-2):100-108
Quantitative in vitro autoradiography was used to assess the effects of kainic acid (KA) and colchicine (COL) on mu and lambda opiate binding in the rat hippocampus. Rats were treated with either systemic KA, a neurotoxin that damages CA3 pyramidal cells and causes seizures and wet-dog shakes, or intrahippocampal COL to destroy dentate granule cells and their mossy fibers, or both toxins. Moderate levels of mu binding were detected in the pyramidal layer and in the stratum lacunosum-moleculare; binding was greater in the ventral hippocampus. Levels of mu binding were markedly increased in all regions 48 h after treatment with KA. Two weeks after COL treatment, there was a modest decrease in mu binding; COL plus KA gave results similar to COL alone. Dense lambda binding was present over the mossy fibers in the stratum lucidum, but was absent over the pyramidal layer. In contrast to mu binding, lambda binding was greater in the dorsal hippocampus. KA alone had little effect on lambda binding, whereas COL alone caused large decreases. KA plus COL caused even larger decreases in lambda binding, to as much as 85% below control. These results demonstrate that mu and lambda binding are localized to different parts of the hippocampus, respond differently to neurotoxin lesions, and likely serve different roles in this brain region. The number of mu sites is responsive to the release of enkephalin; these receptors appear to be linked to opiate-induced hippocampal seizure activity, especially wet-dog shakes. Lambda sites may serve as autoreceptors on mossy fibers.  相似文献   
994.
Reconstitution of the nasal scaffolding with maintainence of soft tissue proportions either following severe facial trauma or as a sequela to aesthetic rhinoplasty misadventures frequently is best achieved using the stability afforded by bone grafts. Split cranial bone grafts offer many advantages and may be the donor site of choice, and may even allow such surgery to be performed on an outpatient basis in some cases. The use of miniplate or screw osteosynthesis, now commonly accepted as a superior technique in craniomaxillofacial procedures, may simplify fixation of these calvarial nasal bone grafts with an apparent decrease in the risk of resorption.  相似文献   
995.
The role of body temperature in the morbidity and mortality resulting from acute severe carbon monoxide (CO) poisoning (2400 ppm CO, 90 min) was investigated using an unanesthetized animal model. Modified Levine prepared female rats (left common carotid artery and jugular cannulated) displayed a lower rate of recovery period (4 hr) re-warming, and an increased mortality rate and behaviorally-assessed neurologic index (NI) compared to normal rats. This indicated their greater susceptibility to CO hypoxia, although the degree of CO-induced hypothermia was the same in both groups. The whole-body cooling of Levine rats to a similar extent prior to CO exposure increased somewhat the post-CO re-warming rate, and marginally decreased NI and mortality during CO exposure (in-CO). In contrast, maintenance of constant body temperature by external heating during CO exposure resulted in a negative post-CO re-warming rate and sharply increased NI and in-CO mortality. Normal euthermic rats were much less severely affected by CO. The results suggest that hypothermia, whether CO-induced or produced by prior cooling, provides measurable protection of brain function during acute severe CO poisoning, and that maintenance of body temperature increases in-CO mortality and interferes with ability to thermoregulate and increases NI in survivors.  相似文献   
996.
997.
The incidence of eye infections in a community is generally accepted as an indicator of the adequacy of water supply for their needs. However, discrepancies in the published results from various studies seem to challenge this view. We have reanalysed the published data on trachoma in relation to the most relevant indicators of water accessibility, using prevalence ratios as the single parameter for risk assessment. A definite trend emerges from this review: the incidence of infectious conjunctivitis is not sensitive to differences in water accessibility; on the other hand, a reduction in the risk of trachoma is consistently associated with better access to water. This conclusion may support the efforts of WHO and other multilateral and bilateral agencies to sustain the commitment towards the water supply sector beyond the International Drinking Water Supply and Sanitation Decade.  相似文献   
998.
999.
M E Baca  A M Mowat  S MacKenzie    D M Parrott 《Gut》1987,28(10):1267-1274
In this study we have investigated whether addition of bone marrow accessory cells or concurrent administration of recombinant IL-2 would allow intraepithelial lymphocytes (IEL) to induce a systemic, lethal GvHR in irradiated hosts. In addition we have studied the ability of IEL to migrate into lymphoid tissues after intravenous injection and compared this with their locomotor capacity in vitro.  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