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   3298篇
  免费   174篇
  国内免费   61篇
耳鼻咽喉   43篇
儿科学   138篇
妇产科学   40篇
基础医学   377篇
口腔科学   82篇
临床医学   344篇
内科学   589篇
皮肤病学   72篇
神经病学   179篇
特种医学   117篇
外科学   776篇
综合类   82篇
一般理论   4篇
预防医学   130篇
眼科学   136篇
药学   176篇
中国医学   13篇
肿瘤学   235篇
  2023年   34篇
  2022年   68篇
  2021年   136篇
  2020年   63篇
  2019年   115篇
  2018年   117篇
  2017年   92篇
  2016年   92篇
  2015年   96篇
  2014年   154篇
  2013年   148篇
  2012年   254篇
  2011年   246篇
  2010年   159篇
  2009年   127篇
  2008年   187篇
  2007年   202篇
  2006年   188篇
  2005年   176篇
  2004年   182篇
  2003年   119篇
  2002年   103篇
  2001年   42篇
  2000年   50篇
  1999年   39篇
  1998年   28篇
  1997年   23篇
  1996年   29篇
  1995年   27篇
  1994年   24篇
  1993年   14篇
  1992年   16篇
  1991年   12篇
  1990年   14篇
  1989年   8篇
  1988年   15篇
  1987年   12篇
  1986年   17篇
  1985年   9篇
  1984年   7篇
  1983年   10篇
  1982年   7篇
  1980年   6篇
  1979年   7篇
  1978年   5篇
  1976年   7篇
  1974年   11篇
  1973年   4篇
  1972年   5篇
  1970年   6篇
排序方式: 共有3533条查询结果,搜索用时 281 毫秒
31.
BACKGROUND CONTEXTThe indication to perform a fusion and decompression surgery as opposed to decompression alone for lumbar degenerative spondylolisthesis (LDS) remains controversial. A variety of factors are considered when deciding on whether to fuse, including patient demographics, radiographic parameters, and symptom presentation. Likely surgeon preference has an important influence as well.PURPOSEThe aim of this study was to assess factors associated with the decision of a Canadian academic spine surgeon to perform a fusion for LDS.STUDY DESIGN/SETTINGThis study is a retrospective analysis of patients prospectively enrolled in a multicenter Canadian study that was designed to evaluate the assessment and surgical management of LDS.PATIENT SAMPLEInclusion criteria were patients with: radiographic evidence of LDS and neurogenic claudication or radicular pain, undergoing posterior decompression alone or posterior decompression and fusion, performed in one of seven, participating academic centers from 2015 to 2019.OUTCOME MEASURESPatient demographics, patient-rated outcome measures (Oswestry Disability Index [ODI], numberical rating scale back pain and leg pain, SF-12), and imaging parameters were recorded in the Canadian Spine Outcomes Research Network (CSORN) database. Surgeon factors were retrieved by survey of each participating surgeon and then linked to their specific patients within the database.METHODSUnivariate analysis was used to compare patient characteristics, imaging measures, and surgeon variables between those that had a fusion and those that had decompression alone. Multivariate backward logistic regression was used to identify the best combination of factors associated with the decision to perform a fusion.RESULTSThis study includes 241 consecutively enrolled patients receiving surgery from 11 surgeons at 7 sites. Patients that had a fusion were younger (65.3±8.3 vs. 68.6±9.7 years, p=.012), had worse ODI scores (45.9±14.7 vs. 40.2±13.5, p=.007), a smaller average disc height (6.1±2.7 vs. 8.0±7.3 mm, p=.005), were more likely to have grade II spondylolisthesis (31% vs. 14%, p=.008), facet distraction (34% vs. 60%, p=.034), and a nonlordotic disc angle (26% vs. 17%, p=.038). The rate of fusion varied by individual surgeon and practice location (p<.001, respectively). Surgeons that were fellowship trained in Canada more frequently fused than those who fellowship trained outside of Canada (76% vs. 57%, p=.027). Surgeons on salary fused more frequently than surgeons remunerated by fee-for-service (80% vs. 64%, p=.004). In the multivariate analysis the clinical factors associated with an increased odds of fusion were decreasing age, decreasing disc height, and increasing ODI score; the radiographic factors were grade II spondylolisthesis and neutral or kyphotic standing disc type; and the surgeon factors were fellowship location, renumeration type and practice region. The odds of having a fusion surgery was more than two times greater for patients with a grade II spondylolisthesis or neutral and/or kyphotic standing disc type (opposed to lordotic standing disc type). Patients whose surgeon completed their fellowship in Canada, or whose surgeon was salaried (opposed to fee-for-service), or whose surgeon practiced in western Canada had twice the odds of having fusion surgery.CONCLUSIONSThe decision to perform a fusion in addition to decompression for LDS is multifactorial. Although patient and radiographic parameters are important in the decision-making process, multiple surgeon factors are associated with the preference of a Canadian spine surgeon to perform a fusion for LDS. Future work is necessary to decrease treatment variability between surgeons and help facilitate the implementation of evidence-based decision making.  相似文献   
32.
Fuchs PN  Roza C  Sora I  Uhl G  Raja SN 《Brain research》1999,821(2):480-486
Clinical and experimental observations suggest that opiates can exert different influences on the perception of stimuli from distinct sensory modalities. Thermally-induced nociception is classically responsive to opiate agonists. mu-Opioid receptor-deficient transgenic mice are more sensitive to thermal nociceptive stimuli and morphine fails to attenuate the nociceptive responses to thermal stimuli in these animals. To enhance our understanding of opiate influences on mechanical sensitivity, we have examined withdrawal responses to a sequence of ascending forces of mechanical stimuli in mice with normal (wild type), half-normal (heterozygous) and absent (homozygous) mu-opioid receptor levels. We report data from mice examined without drug pretreatment or following pretreatment with morphine, the selective kappa-opioid agonist, U50488H, and the selective delta-opioid agonist, DPDPE. Saline-pretreated mice of each genotype displayed similar, monotonically increasing frequency of withdrawal responses to the graded stimuli. Subcutaneously administered morphine produced a dose-dependent reduction in withdrawal responses in wild type and heterozygous mice, but had no significant effect in homozygous mice. Intraventricular administration of DPDPE also reduced the frequency of paw withdrawal (FPW) in wild type mice, but not in homozygous mice. In contrast, systemic U50488H produced a dose-dependent attenuation of paw withdrawal in both wild type and homozygous mice. These findings suggest that (1) interactions of endogenous peptides with mu-opioid receptors may not play a significant role in the response to mechanical stimuli in drug-free animals, and (2) deficiency of mu-opioid receptors has no functional consequence on the response to the prototypical kappa-opioid receptor agonist, but decreases responses to the prototypical mu- and delta-opioid receptor agonists.  相似文献   
33.
AIM: Thoracic outlet syndrome (TOS) is a clinical diagnosis treatable by excision of the first rib. This study was undertaken to assess the alleviation of symptoms following trans-axillary rib excision in patients with a diagnosis of TOS suggested by a positive Elevated Arm Stress Test and, by inference, to estimate the prevalence of the syndrome. METHOD: A retrospective review of trans-axillary first rib excision was performed. No referrals were accepted from outwith the catchment area of our hospital. Post-operative symptomatic improvement was accepted as a confirmation of correct pre-operative diagnosis. RESULTS: Over six years, 52 rib resections were performed in 46 patients, mean age (+/- S.D.) 38.8 (+/- 10.6) years. The indications for surgery were principally neurological symptoms (n = 42 excisions), arterial compromise (n = 5) and venous compromise (n = 5). Symptoms had been present for a mean of 15.8 months prior to surgery. The median follow-up after surgery was 33 months. 42 patients (48 resections) showed immediate improvement in symptoms following surgery, although symptoms recurred in three patients (4 resections) between 6 and 8 months post-operatively. In the final two years of this study, 20 resections resulting in symptomatic improvement were performed, suggesting a prevalence for TOS of at least 10 per 100,000 per year. CONCLUSIONS: Thoracic outlet decompression was performed more frequently in this series than many previous reports, suggesting that TOS may be under-diagnosed.  相似文献   
34.
35.
Twenty-seven patients with idiopathic palmoplanter hyperhidrosis were treated with Iontotherapy over a one year period. In twenty-four cases there was a good response but maintenance therapy was required every 3-4 weeks.KEY WORDS: Iontophoresis, Palmoplanter hyperhidrosis  相似文献   
36.
37.
Epithelioid hemangioma (EH) is a rare benign vascular tumor that occurs in soft tissues and bone and presents between the third and sixth decades of life. Little is known about the clinical course and outcomes of pediatric EH. We report 11 patients diagnosed with EH at a median age of 14.4 years. One patient treated with interferon and one with sirolimus exhibited partial response for >2 years. Although a benign neoplasm, EH is difficult to manage without standard protocols and portends considerable morbidity. Our findings suggest medical management, particularly sirolimus, may benefit these patients; however, long‐term follow‐up is needed.  相似文献   
38.
39.
40.
There are numerous causes of iron deficiency anemia due to gastrointestinal tract bleeding in children. While a very thorough history may elucidate common etiologies, such as cow’s milk protein-induced colitis and nonsteroidal anti-inflammatory drug-related gastritis or peptic ulcer disease, other less frequent causes often present a diagnostic challenge. We present the MR enterography (MRE), CT and Meckel scan findings of ileal dysgenesis coexisting with multiple enteric duplication cysts in a young child who presented with chronic iron deficiency anemia, recurrent gastrointestinal tract bleeding and unexplained bowel perforation. In this case, MRE was able to identify and characterize each individual lesion and directly guide appropriate surgical management.  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