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   33391篇
  免费   2956篇
  国内免费   43篇
耳鼻咽喉   234篇
儿科学   1024篇
妇产科学   980篇
基础医学   4460篇
口腔科学   430篇
临床医学   4150篇
内科学   6661篇
皮肤病学   432篇
神经病学   3518篇
特种医学   838篇
外科学   3443篇
综合类   576篇
一般理论   92篇
预防医学   4561篇
眼科学   399篇
药学   1949篇
中国医学   17篇
肿瘤学   2626篇
  2023年   336篇
  2022年   536篇
  2021年   1084篇
  2020年   716篇
  2019年   1065篇
  2018年   1095篇
  2017年   842篇
  2016年   902篇
  2015年   960篇
  2014年   1253篇
  2013年   1716篇
  2012年   2599篇
  2011年   2506篇
  2010年   1344篇
  2009年   1118篇
  2008年   2031篇
  2007年   1905篇
  2006年   1860篇
  2005年   1746篇
  2004年   1492篇
  2003年   1258篇
  2002年   1100篇
  2001年   413篇
  2000年   466篇
  1999年   424篇
  1998年   306篇
  1997年   218篇
  1996年   206篇
  1995年   162篇
  1994年   128篇
  1993年   139篇
  1992年   280篇
  1991年   294篇
  1990年   272篇
  1989年   246篇
  1988年   214篇
  1987年   235篇
  1986年   254篇
  1985年   249篇
  1984年   191篇
  1983年   170篇
  1982年   132篇
  1981年   125篇
  1980年   107篇
  1979年   179篇
  1978年   116篇
  1977年   99篇
  1975年   102篇
  1974年   106篇
  1973年   105篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Background:Most abnormal parathyroid glands can be removed through a standard cervical incision; even those in the superior mediastinum. Those located in certain areas of the mediastinum, for example posteriorly or in the aortopulmonic window, historically have required excision through a median sternotomy or thoracotomy. Angioablation is a nonsurgical alternative to management of these lesions.Study Design:We present two case reports of mediastinal parathyroid adenomas that were excised thoracoscopically, and review the literature regarding the management of mediastinal parathyroid adenomas.Results:Both patients who underwent precise localization and thoracoscopic excision of their mediastinal parathyroid adenomas had resolution of their hypercalcemia with minimal associated morbidity and shortened recovery periods.Conclusions:We suggest that thoracoscopic excision of mediastinal parathyroid adenomas is the better means of controlling hypercalcemia secondary to parathyroid adenoma in those patients considered for either median sternotomy, thoracotomy or angiographic ablation where the exact location of the lesion can be established preoperatively.  相似文献   
82.
STUDY OBJECTIVE: To determine the effect of baseline complex ovarian cysts on controlled ovarian hyperstimulation and in vitro fertilization (IVF) outcome. DESIGN: Retrospective analysis with stratification by stimulation regimen and the presence or absence of surgically documented endometriosis. PATIENTS: Two hundred sixty-one women undergoing IVF from May 1, 1989 to December 31, 1990. MAIN OUTCOME MEASURES: The outcome measures assessed were the maximum estradiol (E2) concentration on day of human chorionic gonadotropin (hCG) administration, number of follicles with maximum diameter greater than or equal to 15 mm, number of follicles with maximum diameter greater than or equal to 12 mm, number of days to hCG administration, number of ampules of human menopausal gonadotropin (hMG) used, number of oocytes retrieved and fertilized, number of embryos transferred, and pregnancy and cycle cancellation rates. RESULTS: There were no statistical differences between cyst and noncyst groups in any of the above parameters of IVF performance. In a single subgroup, patients with endometriosis stimulated with hMG and patients with cysts had significantly lower E2 concentrations than patients without cysts. CONCLUSION: The presence of a complex cyst on a baseline ultrasound does not appear to adversely affect IVF cycle outcomes.  相似文献   
83.
The anterior cruciate ligament has a complex fiber anatomy and is not considered to be a uniform structure. Current anterior cruciate ligament reconstructions succeed in stabilizing the knee, but they neither fully restore normal knee kinematics nor reproduce normal ligament, function. To improve the outcome of the reconstruction, it may be necessary to reproduce the complex function of the intact anterior cruciate ligament in the replacement graft. We examined the in situ forces in nine human anterior cruciate ligaments as well as the force distribution between the anteromedial and posterolateral bundles of the ligament in response to applied anterioi tibial loads ranging from 22 to 110 N at knee flexion angles of 0–90°. The analysis was performed using a robotic manipulator in conjunction with a universal force-moment sensor. The in situ forces were determined with no device attached to the ligament, while the knee was permitted to move freely in response to the applied loads. We found that the in situ forces in the anterior cruciate ligament ranged from 12.8 ± 7.3 N under 22 N of anterior tibial load applied at 90° of knee flexion to 110.6 ± 14.8 N under 110 N of applied load at 15° of flexion. The magnitude of the in situ force in the posterolateral bundle was larger than that in the anteromedial bundle at knee flexion angles between 0 and 45°, reaching a maximum of 75.2 ± 18.3 N at 15° of knee flexion under an anterior tibial load of 110 N. The magnitude of the in situ force in the posterolateral bundle was significantly affected by knee flexion angle and anterior tibial load in a fashion remarkably similar to that seen in the anterior cruciate ligament. The magnitude of the in situ force in the anteromedial bundle, in contrast, remained relatively constant, not changing with flexion angle. Significant differences in the direction of the in situ force between the anteromedial bundle and the posterolateral bundle were found only at flexion angles of 0 and 60° and only under applied anterior tibial loads greater than 66 N. We have demonstrated the nonuniformity of the anterior cruciate ligament under unconstrained anterior tibial loads. Our data further suggest that in order for the anterior cruciate ligament replacement graft to reproduce the in situ forces of the normal anterior cruciate ligament, reconstruction techniques should take into account the role of the posterolateral bundle in addition to that of the anteromedial bundle.  相似文献   
84.
The organization of daily procedures within the operating theatre is considered in terms of rival perspectives on their patient held by surgeon and anaesthetist. The privileging of the surgeon's authority is challenged in anaesthetists' efforts to fabricate a distinctive position on the patient. While surgeons focus on patient as the carrier of disease, for the anaesthetist, the focus is upon the patient's complement of fitness. A postmodern analysis of the organization of surgery reflects the continual struggle between the two specialisms to privilege its particular definition of the surgical patient. In some circumstances, the struggle can have damaging consequences for patient care.  相似文献   
85.
86.
87.
88.
89.
OBJECTIVE: The aim of the present study was to examine the nature of previously reported deficits in sustained attention and response inhibition in adults with the developmental disorder, phenylketonuria (PKU). METHODS: This study used event-related potentials (ERPs) to examine the performance of PKU adults (n=9) and a matched control group (n=9) on a visual Go-Nogo task. RESULTS: Comparison of behavioural measures between the PKU and control groups failed to reach statistical significance, yet analysis of the ERPs showed statistically significant amplitude reductions in the P1 and N1 components elicited following presentation of stimuli, and a reduction in the amplitude of the N2 component elicited following presentation of Nogo stimuli. CONCLUSIONS: These results suggest that adults with PKU, despite being continuously treated from birth, manifest subtle impairments in distinct aspects of information processing including early sensory processing of visually presented information, as well as impairments in inhibitory functions. SIGNIFICANCE: The results contribute to an understanding of the neurophysiological mechanisms that are implicated in PKU and highlight the sensitivity of ERP techniques for the identification of the loci of information processing deficits in clinical groups.  相似文献   
90.
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