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   5712篇
  免费   417篇
  国内免费   19篇
耳鼻咽喉   71篇
儿科学   160篇
妇产科学   109篇
基础医学   1024篇
口腔科学   59篇
临床医学   623篇
内科学   1265篇
皮肤病学   186篇
神经病学   539篇
特种医学   202篇
外科学   784篇
综合类   42篇
一般理论   3篇
预防医学   367篇
眼科学   102篇
药学   309篇
中国医学   6篇
肿瘤学   297篇
  2023年   42篇
  2022年   46篇
  2021年   152篇
  2020年   121篇
  2019年   158篇
  2018年   156篇
  2017年   142篇
  2016年   162篇
  2015年   179篇
  2014年   219篇
  2013年   275篇
  2012年   429篇
  2011年   433篇
  2010年   211篇
  2009年   209篇
  2008年   373篇
  2007年   355篇
  2006年   337篇
  2005年   304篇
  2004年   336篇
  2003年   276篇
  2002年   264篇
  2001年   46篇
  2000年   27篇
  1999年   34篇
  1998年   60篇
  1997年   62篇
  1996年   61篇
  1995年   43篇
  1994年   37篇
  1993年   39篇
  1992年   38篇
  1991年   21篇
  1990年   25篇
  1989年   24篇
  1988年   29篇
  1987年   24篇
  1986年   25篇
  1985年   30篇
  1984年   15篇
  1983年   32篇
  1982年   33篇
  1981年   48篇
  1980年   22篇
  1979年   14篇
  1978年   18篇
  1977年   22篇
  1976年   25篇
  1975年   14篇
  1974年   12篇
排序方式: 共有6148条查询结果,搜索用时 15 毫秒
1.
2.
3.
For 50 years now, sacrospinous ligament fixation (SSLF) has been used to treat pelvic organ prolapse consequent on altered integrity of the pelvic myofascial structures. It is usually performed vaginally, but it has recently been performed laparoscopically through either an anterior or a posterior approach, with the broad ligament as a landmark to differentiate the two. In the present study, these two laparoscopic approaches were assessed using Thiel-embalmed cadavers. The anterior and posterior approaches were compared in terms of the closest distance to anatomical structures at risk, including pelvic viscera, the obturator nerve, and vascular structures. The posterior approach was more often closer to the investigated vessels and the rectum. The obturator nerve and the ureter were close to both the anterior and posterior approaches. The urinary bladder was closer using the anterior approach. From an anatomical standpoint, therefore, the anterior laparoscopic approach for SSLF is more likely to cause injury to the urinary bladder, whereas the posterior approach is more prone to causing rectal and vessel injuries. This study illustrates, from a basic science perspective, the importance of combining fascia research, novel endoscopic or minimally invasive surgical exposures informed by anatomy, and contemporary trends in gynecology in order to improve patient outcomes. Clin. Anat. 33:522–529, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
4.
5.
We report our experience with elastic stable intramedullary titanium nailing (ESIN) of femoral shaft fractures in children. From 1998 to 2001, we treated 31 children (20 boys), median age 6 (4-11) years, with ESIN for 29 closed and 2 grade I open femoral shaft fractures. We reviewed 30 children clinically after median 1.5 (1-3) years. Their median hospital stay was 6 (2-20) days. All fractures were radiographically united at a median of 7 (5-9) weeks. The nails were removed in 29 children after a median of 22 (6-38) weeks postoperatively. At follow-up, we found a leg-length discrepancy up to 1 cm in 6 children and 10 degrees of internal rotational deformity in 1 child. No angular deformity had occurred. Elastic stable intramedullary nailing seems to be a safe method for the treatment of femoral shaft fractures in children between 4 and 11 years of age.  相似文献   
6.
Intrafamilial variation of the phenotype in Bardet-Biedl syndrome   总被引:3,自引:0,他引:3       下载免费PDF全文
AIMS—To describe the variation of the phenotype within families with several individuals with Bardet-Biedl syndrome.
METHODS—The phenotypes of affected siblings in 11 Scandinavian families were compared with two or more members who had at least three of the features: retinal dystrophy, polydactyly, obesity, hypogenitalism, and mental retardation. Individuals without retinal dystrophy were excluded.
RESULTS—Intrafamilial variation of expressivity of the features obesity, polydactyly, abnormal radiograms of the extremities, hypogenitalism, short stature, paraplegia, and dental abnormalities was found. The retinal dystrophy varied with respect to both the onset of symptoms and the course of the disease. The morphology of the fundus, however, was consistent within the families. The disorder showed statistically significant genetic linkage to the BBS4 locus on chromosome 15 in the affected siblings in two of the families, but the clinical features in these patients did not differ from the other cases of Bardet-Biedl syndrome.
CONCLUSION—Comparison of siblings with the Bardet-Biedl syndrome showed variation of the typical features. In addition, the course of retinal dystrophy varied. No distinctive clinical features were found to separate the BBS4 phenotype from the remaining patients.

  相似文献   
7.
AIMS: The developing world is particularly at risk of an increasing health burden due to an increased prevalence of Chronic Obstructive Pulmonary Disease (COPD) secondary to increasing tobacco consumption. However, research is scarce. The objectives of this study were to assess the current competence for diagnosing COPD in primary care in a resource-limited setting in Brazil, and to develop a local patient profile for case-finding. METHODS: 34 general practitioners (GPs) in five areas of northern Brazil recruited adult patients with principal complaints of cough and/or shortness of breath who then had spirometry (n = 142). RESULTS: For the dichotomous variable 'COPD' the degree of agreement between GP diagnosis (n = 64, 18.3%) and spirometric outcome (n = 36, 25.4%) was poor, with Kappa = 0.055 (SE 0.087) and DOR = 1.35. False-positive and false-negative diagnosis proportions were 19.8% and 75%, respectively. Independent risk factors were 'smoking history of more than five pack years' and 'presence of both dyspnoea and cough'. It requires the testing of 2.2 smokers with more than five pack years to detect one patient at risk. CONCLUSIONS: COPD is a common yet underdiagnosed disease in Brazilian primary care. Spirometry improves diagnostic competence and case-finding substantially. If applied in a pre-selected high-risk population, we believe spirometry can be a cost-effective diagnostic tool for case-finding in the resource-limited setting. This study provides important baseline information for effective guideline implementation.  相似文献   
8.
Studies of post-lesional reorganization of central nervous connections have shown that central nerve fibers respond to nearby denervation by sprouting and formation of new terminals. The connections in the central nervous system (CNS) are accordingly much more plastic than was thought for a long time. This has revived the interest in transplantation of central nervous tissue. In this study we present some historical data on CNS transplantation supplemented by recent results obtained in our laboratory. Pieces of hippocampal tissue from embryonic or early postnatal rats were transplanted to different parts of the brain of littermates or adult rats. About two-thirds of the transplants were recovered after survival times ranging from 4 d to 2 years, and their cytological organization and intrinsic connections were monitored by cell and fiber stains and histochemical methods (AChE staining and Timm sulphide silver method). Comparison with both a normal and a lesioned control material revealed that in most transplants the tissue had developed as it does when left in situ in the donor brain, but deprived of its major afferent connections. In several instances we found evidence of a major exchange of connections between the transplants and host brains. The conditions needed for this to occur appeared to involve growth stimulation of host brain fibers by transection (host to transplant) and denervation of host neuropil (transplant to host). In cases where these conditions are met, the use of transplants may have future implications in attempts to repair lesions in the central nervous systems.  相似文献   
9.
10.
Brain function requires oxygen and maintenance of brain capillary oxygenation is important. We evaluated how faithfully frontal lobe near-infrared spectroscopy (NIRS) follows haemoglobin saturation (SCap) and how calculated mitochondrial oxygen tension (PMitoO2) influences motor performance. Twelve healthy subjects (20 to 29 years), supine and seated, inhaled O2 air-mixtures (10% to 100%) with and without added 5% carbon dioxide and during hyperventilation. Two measures of frontal lobe oxygenation by NIRS (NIRO-200 and INVOS) were compared with capillary oxygen saturation (SCap) as calculated from the O2 content of brachial arterial and right internal jugular venous blood. At control SCap (78%+/-4%; mean+/-s.d.) was halfway between the arterial (98%+/-1%) and jugular venous oxygenation (SvO2; 61%+/-6%). Both NIRS devices monitored SCap (P<0.001) within approximately 5% as SvO2 increased from 39%+/-5% to 79%+/-7% with an increase in the transcranial ultrasound Doppler determined middle cerebral artery flow velocity from 29+/-8 to 65+/-15 cm/sec. When SCap fell below approximately 70% with reduced flow and inspired oxygen tension, PMitoO2 decreased (P<0.001) and brain lactate release increased concomitantly (P<0.001). Handgrip strength correlated with the measured (NIRS) and calculated capillary oxygenation values as well as with PMitoO2 (r>0.74; P<0.05). These results show that NIRS is an adequate cerebral capillary-oxygenation-level-dependent (COLD) measure during manipulation of cerebral blood flow or inspired oxygen tension, or both, and suggest that motor performance correlates with the frontal lobe COLD signal.  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