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   13958篇
  免费   1063篇
  国内免费   39篇
耳鼻咽喉   77篇
儿科学   359篇
妇产科学   171篇
基础医学   1824篇
口腔科学   273篇
临床医学   1467篇
内科学   2758篇
皮肤病学   133篇
神经病学   1376篇
特种医学   568篇
外科学   1935篇
综合类   145篇
一般理论   32篇
预防医学   1680篇
眼科学   241篇
药学   987篇
中国医学   20篇
肿瘤学   1014篇
  2024年   11篇
  2023年   138篇
  2022年   212篇
  2021年   475篇
  2020年   289篇
  2019年   397篇
  2018年   448篇
  2017年   352篇
  2016年   376篇
  2015年   442篇
  2014年   546篇
  2013年   751篇
  2012年   1154篇
  2011年   1128篇
  2010年   698篇
  2009年   577篇
  2008年   985篇
  2007年   935篇
  2006年   893篇
  2005年   874篇
  2004年   808篇
  2003年   738篇
  2002年   611篇
  2001年   122篇
  2000年   74篇
  1999年   80篇
  1998年   120篇
  1997年   92篇
  1996年   79篇
  1995年   59篇
  1994年   61篇
  1993年   51篇
  1992年   53篇
  1991年   39篇
  1990年   53篇
  1989年   45篇
  1988年   33篇
  1987年   30篇
  1986年   20篇
  1985年   25篇
  1984年   26篇
  1983年   20篇
  1982年   23篇
  1981年   16篇
  1980年   15篇
  1979年   18篇
  1978年   15篇
  1977年   10篇
  1976年   7篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.
Acromegaly is a rare, chronic, and debilitating disease that results from excessive growth hormone production. Clinically, this disease is associated with enlargement of soft tissue, excessive skeletal growth, and increased risk of cardiovascular disease. Acromegaly is often diagnosed late, when a wide range of comorbidities may already be present. First-line therapy for acromegaly is typically surgery; but a number of highly-specific pharmacological agents have recently enabled a more aggressive medical management of acromegaly. Since surgical cure of acromegaly is low for macroadenomas, medical control of active acromegaly is an important component of treatment. There are no published US data currently available regarding real-world rates of comorbidities and treatment patterns among patients with acromegaly. This retrospective study examined the comorbidities and treatment patterns of 949 health plan enrollees, who had acromegaly diagnosis and/or procedure codes in an administrative claims database from July 1, 2002 through June 30, 2010. Acromegaly was associated with high rates of hypertension and diabetes along with a number of other comorbidities. The incidence of comorbidities was highest among patients with acromegaly-related treatment, which may have resulted, in part, from inadequate disease management and/or poor disease control. Unexpectedly, 55 % of patients identified with acromegaly received no treatment for acromegaly (i.e., surgery, radiotherapy, and medication) and only 28 % received a medication treatment during the observation period. However, some patients may have received a curative surgery prior to the observation period, which may have reduced the use of other acromegaly-related treatments during the study period. Of those treated with medications, the most common first medications were octreotide, cabergoline, and bromocriptine. Given the high incidence of serious comorbidities associated with active acromegaly, earlier diagnosis and treatment, along with appropriate follow-up care, may potentially avoid the life-long consequences of uncontrolled disease.  相似文献   
84.
85.
86.
Recently, early investment in the human capital of children from socially disadvantaged environments has attracted a great deal of attention. Programs of such early intervention, aimed at children’s health and well-being, are spreading considerably in the US and are currently being tested in several European countries. In a discrete version of the Mirrlees model with a parents’ and a children’s generation, we model the intra-generational and the inter-generational redistributional consequences of such intervention programs. It turns out that the parents’ generation loses whenever such intervention programs are implemented. Furthermore, the rich part of the children’s generation always benefits. Despite the expectation that early intervention puts the poor descendants in a better position, our analysis reveals that the poor among the children’s generation may even be worse off, if the effect of early intervention on their productivity is not large enough.  相似文献   
87.
Cancer cluster studies in North Carolina identified several communities in which there existed an elevated risk of brain cancer. These findings prompted a series of case-control studies. The current article, which originated from the results of the 3rd of such studies, is focused on inclusion of the earth's own geomagnetic fields that interact with electromagnetic fields generated from distribution power lines. This article also contains an assessment of the contribution of confounding by residential (e.g., urban, rural) and case characteristics (e.g., age, race, gender). Newly diagnosed brain cancer cases were identified for a 4-county region of central North Carolina, which the authors chose on the basis of the results of earlier observations. A 3:1 matched series of cancer cases from the same hospitals in which the cases were diagnosed served as the comparison group. Extensive geographic information was collected and was based on an exact place of residence at the time of cancer diagnosis, thus providing several strategic geophysical elements for assessment. The model for this assessment was based on the effects of these two sources of electromagnetic fields for an ion cyclotron resonance mechanism of disease risk. The authors used logistic regression models that contained the predicted value for the parallel component of the earth's magnetic field; these models were somewhat erratic, and the elements were not merged productively into a single statistical model. Interpretation of these values was difficult; therefore, the modeled values for the model elements, at progressive distances from the nearest power-line segments, are provided. The results of this study demonstrate the merits of using large, population-based databases, as well as using rigorous Geographic Information System techniques, for the assessment of ecologic environmental risks. The results also suggest promise for exposure classification that is compatible with the theoretical biological mechanisms posited for electromagnetic fields.  相似文献   
88.
Objective. The purpose of this study was to describe an air transport service's protocol for direct transport of patients with abdominal aortic aneurysm leak (AAAL) into receiving hospital operating rooms (ORs). Methods. This retrospective consecutive-case analysis examined AAAL patients undergoing nurse-paramedic Boston MedFlight (BMF) transport during 1999–2004, who were taken directly into ORs at four academic centers. BMF uses a rotating roster system to assign receiving hospitals when referring physicians have no preidentified receiving facility, but this practice may prolong patient transport or be associated with less diagnostic certainty, andthus more delay, at receiving hospitals. Thus, the study compared “Roster” versus “Non-roster” patients' time andoutcome end points. Continuous nonparametric data (e.g., time intervals) were described with median andinterquartile range (IQR). Chi-square andKruskal-Wallis tests were used for univariate comparisons; regression analysis assessed dependent variables while adjusting for covariates (e.g., transport mileage). Results. There were 29 direct-to-OR transports, with median distance of 30 miles. All patients had AAAL diagnosis confirmed; 51.7% survived. System performance for end points was similar as assessed between Roster versus Non-roster patients. Conclusions. Interfacility direct-to-OR transport of AAAL patients is feasible. Use of a roster system allows for timely transport facilitation for patients needing specialized care; roster patients achieve similar end points as did patients who had already-identified receiving hospitals upon air medical transport request.  相似文献   
89.
90.
The aim of the paper is to describe the medial portal technique for anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Placement of an ACL graft within the anatomical femoral and tibial attachment sites is critical to the success and clinical outcome of ACL reconstruction. Non-anatomical ACL graft placement is the most common technical error leading to recurrent instability following ACL reconstruction. ACL reconstruction has commonly been performed using a transtibial tunnel technique in which the ACL femoral tunnel is drilled through a tibial tunnel positioned in the posterior half of the native ACL tibial attachment site. ACL reconstruction performed using a transtibial tunnel technique often results in a vertical ACL graft, which may fail to control the combined motions of anterior tibial translation and internal tibial rotation which occur during the pivot-shift phenomenon. The inability of a vertically oriented ACL graft to control these combined motions may result in the patient experiencing continued symptoms of instability due to the pivot-shift phenomenon. The medial portal technique in which the ACL femoral tunnel is drilled through an anteromedial or accessory anteromedial portal allows consistent anatomical ACL tunnel placement. This paper describes the advantages of the medial portal technique, indications for the technique, patient positioning, proper portal placement, anatomical femoral and tibial tunnel placement, graft tensioning and fixation.  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