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   5678篇
  免费   407篇
  国内免费   105篇
耳鼻咽喉   31篇
儿科学   158篇
妇产科学   100篇
基础医学   696篇
口腔科学   53篇
临床医学   729篇
内科学   1049篇
皮肤病学   88篇
神经病学   861篇
特种医学   414篇
外科学   837篇
综合类   92篇
一般理论   1篇
预防医学   281篇
眼科学   96篇
药学   412篇
中国医学   4篇
肿瘤学   288篇
  2021年   58篇
  2020年   42篇
  2019年   61篇
  2018年   78篇
  2017年   68篇
  2016年   85篇
  2015年   97篇
  2014年   105篇
  2013年   148篇
  2012年   221篇
  2011年   204篇
  2010年   152篇
  2009年   170篇
  2008年   238篇
  2007年   306篇
  2006年   240篇
  2005年   273篇
  2004年   212篇
  2003年   242篇
  2002年   229篇
  2001年   229篇
  2000年   194篇
  1999年   163篇
  1998年   85篇
  1997年   79篇
  1996年   79篇
  1995年   84篇
  1994年   66篇
  1993年   85篇
  1992年   106篇
  1991年   110篇
  1990年   119篇
  1989年   128篇
  1988年   114篇
  1987年   103篇
  1986年   100篇
  1985年   130篇
  1984年   87篇
  1983年   70篇
  1982年   50篇
  1981年   44篇
  1980年   44篇
  1979年   76篇
  1978年   48篇
  1977年   58篇
  1976年   45篇
  1974年   57篇
  1973年   49篇
  1972年   38篇
  1969年   34篇
排序方式: 共有6190条查询结果,搜索用时 0 毫秒
1.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
2.
Recurrent dislocation of the patella and the Goldthwait operation   总被引:1,自引:0,他引:1  
In this study 17 patients with recurrent dislocation of the patella were followed up 10 years after their Goldthwait operation. The subjective and clinical findings were excellent or good in 70%. X-radiographs indicated osteoarthritis of the femoropatellar joint in 60%. Concerning the aetiopathological factors, we found an increased external torsion of the afflicted extremity (measured by computed tomography).  相似文献   
3.
BACKGROUND. Studies have documented the potential contributions of preventive health care programs. Yet little is known about which screening tests should be included in public health programs for older persons. This study offers recommendations regarding these tests. METHODS. The recommendations come from synthesizing the findings of the US Preventive Services Task Force, the literature, and the consensus of experts in geriatrics, gerontology, and health policy research. The literature was evaluated to identify methodologically sound studies of the prevalence of selected disorders and benefits and availability of screening procedures for those disorders. Experts from various fields specializing in the care of the elderly formed panels to assist in evaluating the literature and providing further information from gerontological and public health perspectives. RESULTS. We recommend vision testing for refractive error; inspection of the skin surface for fungal infection and skin cancer, drug eruptions, and xerosis; a history for symptoms of xerosis; audiometric testing for presbycusis; surveys for hearing loss; otoscopic inspection for cerumen impaction; dental examination for caries; measurement of blood pressure for hypertension; and breast examination and mammography for cancer. CONCLUSIONS. Our study suggests that these screening procedures are useful for public health screening programs. More information is needed on the effects of screening services on the health and functioning of older persons.  相似文献   
4.
5.
6.
Pain in or symptomatic destruction of any number of the joints of the hindfoot can have several causes. As well as primary osteoarthritis, these include secondary arthrotic changes following fractures (especially of the talus and/or calcaneus), muscular and/or tenoligamentous instability (e.g., rupture of the posterior tibialis tendon, poliomyelitis, Charcot-Marie-Tooth disease), spastic and flaccid paresis of the lower leg and foot, late stages of various inflammatory arthritides (rheumatoid arthritis, seronegative spondarthritis, collagenoses), and neuropathic diseases with impaired depth perception (Charcot disease of the foot in diabetes mellitis, for example). As a general policy, only joints that are causing symptoms, are clearly arthritic, or are involved in a fixed foot deformity should be fused, so that as much of the residual hindfoot motion as possible is preserved. This helps to restrict future osteoarthritis in adjacent joints. The use of screws rather than staples seems to increase the fusion rates because this technique allows compression on the fusion.  相似文献   
7.
Non-ionic contrast media (CM) are proven to be significantly safer than the high osmolar ionic contrast media (HOCM). Nevertheless deaths are reported after administration of non-ionic agents. The aim of the study was to investigate the rate of adverse reactions to non-ionic CM with special regard to high-risk patients and the effects of premedication with H1-and H2-receptor antagonists.In a prospective study conducted over about 2 years 12 995 examinations with intravenous or intra-arterial non-ionic CM were evaluated. Premedication with H1-and H2-antagonists was used in 1276 high-risk patients with known adverse reaction to CM, history of allergy or severe cardiac or pulmonary disease. 229 patients received no premedication inspite of known risk factors. In total, there were 143 (1.10%) adverse reactions (mild in 0.58%, moderate in 0.41% and severe in 0.05%). In high-risk patients there were adverse reactions in 4.37% without and in 1.57% with premedication. There were no severe adverse reactions in the high-risk patients after premedication. The age of the patient, CM dosage and CM concentration were not shown to be risk factors in the present study. In conclusion, the additional premedication with H1- and H2-antagonists could be an effective agent to reduce the risk of mild and moderate adverse reactions and to avoid severe adverse reactions in high-risk patients. Correspondence to: U. Fink  相似文献   
8.
The physiological phenomenon of changes in callus formation during distraction was first described by Codivilla at the beginning of this century. Having investigated and proved the influence of tension stress on callus formation, Ilizarov used this as a method to treat limb shortening and deformities. Because of his remarkable results we introduced this method in our hospital in 1990, using the original Ilizarov ring fixator. From November 1990 to December 1991, we used this technique in 10 cases of combined post-traumatic bone shortening with deformity (the tibia was affected in six patients, the femur in three and the forearm in one). The mean shortening was 3.1 cm, the mean varus or valgus deformity 9.5 degrees, the mean anteflexion or recurvation 8.3 degrees, and the mean rotation deformity 8.5 degrees. Distraction/correction lasted between 8 and 55 days (mean: 37 days). Fixation was necessary for between 60 and 339 days. If corticotomy was performed in the diaphyseal bone, fixation lasted almost twice as long (11.33 days/mm lengthening) as in the metaphyseal area (6.55 days/mm lengthening). There were 14 complications, most of which were considered minor. The latter included pin infections (4), wire breaking (1) and restricted range of motion of the knee or ankle (5). Among the major complications were two nerve irritations, which recovered spontaneously, and two pin-induced local bone infections, which required surgical intervention. Achievement of the goals of treatment-complete correction of shortening and deformity-was not affected by these complications.  相似文献   
9.
Independent Practice Associations (IPAs) are the fastest growing segment of the Health Maintenance Organization (HMO) industry, but little is known about their provision of health promotion and disease prevention to subscribers. To examine the extent to which IPA policies encourage health promotion and disease prevention, we interviewed medical directors and other senior administrators of six newly developing IPA-HMOs in New York City. We also reviewed promotional literature to assess how extensively health promotion and disease prevention were marketed to the potential subscriber. Although medical protocols for preventive screening exist in most IPAs, compliance with guidelines is left largely to the individual physician's judgment for implementation. IPA respondents suggested that their physician panels are oriented toward prevention, but there is uncertain evidence in this regard, and incentive payments could discourage referrals for screening. Health education programs are sporadic. Health promotion and disease prevention do not appear to be a high priority among six newly established IPAs in New York City. We recommend several steps that would encourage IPA-HMOs to increase their health promotion activities.  相似文献   
10.
In 1984, 154 physicians who had completed residencies in internal medicine at 15 major teaching hospitals in 1982 evaluated their residency training in ambulatory care. A majority of the physicians would have liked more experience in practical areas related to career planning and office management, more input from subspecialties such as orthopedics and dermatology, greater knowledge about the management of psychosocial problems, and more information about exercise and nutrition. Although many physicians also wanted more time devoted to several other topics, less than 20 percent recommended spending less time on 26 of the 27 topics being evaluated. Since these recommendations are similar to those reported in evaluation studies published over the past 25 years, it appears that training programs in internal medicine have not been successful in restructuring their curricula to meet many of the needs of practicing physicians.  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