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   13921篇
  免费   1245篇
  国内免费   39篇
耳鼻咽喉   118篇
儿科学   536篇
妇产科学   276篇
基础医学   1693篇
口腔科学   271篇
临床医学   1513篇
内科学   2694篇
皮肤病学   147篇
神经病学   1348篇
特种医学   693篇
外科学   1969篇
综合类   344篇
一般理论   18篇
预防医学   1348篇
眼科学   365篇
药学   1052篇
中国医学   10篇
肿瘤学   810篇
  2022年   131篇
  2021年   235篇
  2020年   146篇
  2019年   246篇
  2018年   300篇
  2017年   222篇
  2016年   240篇
  2015年   288篇
  2014年   368篇
  2013年   519篇
  2012年   793篇
  2011年   788篇
  2010年   443篇
  2009年   367篇
  2008年   695篇
  2007年   712篇
  2006年   705篇
  2005年   659篇
  2004年   691篇
  2003年   567篇
  2002年   591篇
  2001年   363篇
  2000年   343篇
  1999年   320篇
  1998年   191篇
  1997年   158篇
  1996年   162篇
  1995年   121篇
  1994年   134篇
  1993年   147篇
  1992年   284篇
  1991年   246篇
  1990年   211篇
  1989年   207篇
  1988年   201篇
  1987年   194篇
  1986年   183篇
  1985年   174篇
  1984年   130篇
  1983年   110篇
  1982年   102篇
  1981年   87篇
  1980年   106篇
  1979年   86篇
  1978年   86篇
  1977年   88篇
  1976年   98篇
  1974年   76篇
  1973年   94篇
  1972年   86篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
To determine whether the Osgood-Schlatter lesion (OS) is produced by avulsion fracture or injury to the patellar tendon, all images obtained in 28 cases of OS in 20 patients (16 scintigrams, 34 computed tomographic [CT] scans, and 27 magnetic resonance [MR] images) were retrospectively analyzed. In 21 cases, imaging was performed before and after treatment; in 20 cases, relief from pain was complete at the time of repeat examination. In all patients (100%), abnormal size of the tendon, decreased attenuation, and increase in signal intensity were compatible with the CT and MR imaging appearance of tendinitis. Distended deep infrapatellar bursa was a frequent finding, particularly on MR studies. These abnormalities had partially disappeared at follow-up examination. An ossicle was seen in only nine of 28 cases (32%); in three of seven cases with follow-up, the ossicle remained nonunited to the tibial tuberosity on follow-up studies despite relief from symptoms. This implies that healing of fracture is not essential for relief from symptoms. These results strengthen the argument that in most cases of OS, insult to the tendon and associated soft tissues, rather than avulsion fracture, causes OS.  相似文献   
52.
Abstract Factors influencing the remarkable growth of home health care include increased elderly population, decreased average length of hospital stay, and technological advancements that reduce the need for hospitalization. Societal changes have prompted increasing concern about personal risk to home care providers. The purpose of this pilot study was to: 1) ascertain factors related to perception of risk by home health care administrators and staff and to identify strategies used by home health care administrators to reduce risk to staff; and 2) determine whether quality of care is affected when home-visit situations present risk. A convenience sample of 36 home health care administrators and 62 staff was surveyed about risks and measures provided by the home health care agency to minimize risk. Factors associated with risk are geographic location, high incidence of crime, inappropriate patient or caregiver behavior, infectious diseases, and evening assignments. Strategies used to minimize risk include safety programs, preplanning of visits, personal protective equipment, escorts, and buddy systems. Perceived ability to refuse high-risk assignments, however, is questionable, as 66% of the staff stated that they leave a situation "as soon as possible." These findings will be used to strengthen inservice programs and to provide a basis for future studies.  相似文献   
53.
54.
55.
56.
Context.— The use of serologic testing to diagnose Lyme disease (LD) is a source of controversy. Expert recommendations also discourage the routine use of antibiotic therapy for prophylaxis of LD following tick bites, but the extent to which physicians in endemic areas have adopted these recommendations is not known. Objective.— To assess the pattern of use of serologic testing and antibiotic therapy for tick bites and LD and associated charges for management in an endemic area. Design.— Active surveillance of patient-physician encounters for tick bites and LD. Setting.— Primary care practices on the Eastern Shore of Maryland. Patients.— Consecutive sample of 232 patients with tick bites, LD (defined by physician diagnosis in medical record), and suspected LD (physician notation of possible, but not definite LD) seen in 1995. Main Outcome Measures.— Serologic testing for LD, test results, antibiotic therapy, and direct costs of management. Results.— Surveillance identified 142 patients (61.2%) with diagnoses of tick bites, 40 patients (17.2%) with LD, and 50 patients (21.6%) with suspected LD. Of the 142 patients seen for tick bites, 95 (67%) underwent serologic testing for LD. Of these, 93 patients had initial negative or equivocal results; 24 (26%) of the 93 had convalescent testing, with 1 seroconversion. Seventy-eight patients (55%) with a diagnosis of tick bite received antibiotic therapy. No patients with tick bite developed clinical LD. Serologic testing for LD was performed for 36 patients (90%) with a diagnosis of LD and 46 patients (92%) with suspected LD. In most cases, antibiotics were prescribed before serologic test results became available. Convalescent testing was not performed for 37 (86%) of the 43 patients with suspected LD who had initial negative or equivocal results. Of these 37 patients, 25 (68%) did not receive antibiotic therapy. Direct charges for treatment of these 232 patients totaled $47595, one third of which was attributable to serologic testing. A total of 32% of direct charges were for patients with tick bites, 48% were for patients with LD, and 20% were for patients with suspected LD. Conclusions.— In this setting, most patients consulting physicians for tick bites received prophylactic antibiotic therapy of unproven efficacy and underwent unnecessary, costly serologic testing. Despite almost universal use in this study, serologic testing for LD did not appear to influence treatment of patients diagnosed as having LD.   相似文献   
57.
The role of the ethanol training dose on the ability of the selective 5-HT1 agonist TFMPP (m-trifluoromethylphenylpiperazine) to produce ethanol-like discriminative stimulus effects was evaluated in three groups of rats trained to discriminate 1.0 g/kg (n=5), 1.5 g/kg (n=6) or 2.0 g/kg (n=7) ethanol (IG) from water using a two-lever procedure with food reinforcement available under a fixed ratio 20 (FR 20) schedule. Ethanol generalization gradients were comparable in the three groups, indicating few potency differences in the ethanol stimulus across training dose. However, the ability of TFMPP (0.1–1.7 mg/kg; IP) to substitute for ethanol was dependent on the training dose. TFMPP resulted in partial substitution in the 1.0 g/kg group, complete substitution for 1.5 g/kg group and no substitution in the 2.0 g/kg ethanol training group. The results indicate a serotonergic component to the discriminative stimulus effects of an intermediate dose of ethanol that is not prominent as the dose of ethanol is raised. These data add further support for the hypothesis that ethanol produces a mixed discriminative cue, the components of which are not uniformly amplified when the dose of ethanol is increased.  相似文献   
58.
The "Learn Not to Burn" prevention program is a burn prevention curriculum sponsored by the North Carolina Jaycee Burn Center, the State Department of Public Instruction, and the North Carolina Department of Insurance Fire and Rescue Division. The goal of the program is to reduce burn-related deaths and injuries in North Carolina through burn prevention education by making the "Learn Not to Burn" curriculum available to primary school children across the state at no cost to the schools. The curriculum instrument is a reusable notebook that provides a means for teachers to integrate burn prevention into regular class subject areas. At the time of initiation of this study approximately 70% of the school systems in North Carolina had been provided with the "Learn Not to Burn" curriculum.  相似文献   
59.
We evaluated the relationship between life events, social support, coping, and depression in 27 male inpatients meeting the requirements for Research Diagnostic Criteria major depressive disorder and in 35 age- and sex-matched nonpatients. Overall, the hospitalized depressed patients reported significantly more events and difficulties than did the controls, but this difference in statistical significance disappeared after excluding from analysis "non-independent" happenings which could have been brought on by depression. More hospitalized depressed patients (23 of 27, or 85%) than controls (8 of 35, or 22.9%) experienced markedly threatening events and difficulties ("marked adversities") in the 6 months before their interview. The depressed group also reported having significantly fewer social supports, being less satisfied with the emotional component of this support, and using more emotion-focused coping than the controls. A discriminant analysis predicted depressive status from a combination of marked adversities, reduced number of social supports, and greater use of emotion-focused coping. The results indicate that the relationship of life events to depression is complex. The excess number of events might be partly a product of dysfunctional behavior that "produces" depression-related events which might, in turn, exacerbate depression; simultaneously, patients are more likely to experience highly adverse events which might precipitate the depression in the first place. Reduced social supports and the use of emotion-focused coping appear to also be associated with hospitalization for major depression.  相似文献   
60.
Pancreatic pseudotumor in pancreas divisum: CT characteristics   总被引:1,自引:0,他引:1  
We report a case in which a focally spared area of pancreatic tissue in a gland otherwise replaced by fat created a "pseudomass" mimicking neoplasm on sonography and CT. The "pseudomass" appearance was related to the anomalous ductal anatomy in pancreas divisum. The spared area of pancreas creating a "pseudomass" was drained by the dorsal duct and the remainder of the pancreas that had undergone relative fatty replacement was drained by the ventral duct.  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