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   1460篇
  免费   94篇
  国内免费   12篇
耳鼻咽喉   36篇
儿科学   37篇
妇产科学   26篇
基础医学   167篇
口腔科学   35篇
临床医学   117篇
内科学   413篇
皮肤病学   12篇
神经病学   98篇
特种医学   26篇
外科学   237篇
综合类   10篇
预防医学   58篇
眼科学   30篇
药学   103篇
中国医学   2篇
肿瘤学   159篇
  2023年   11篇
  2022年   18篇
  2021年   35篇
  2020年   21篇
  2019年   29篇
  2018年   38篇
  2017年   20篇
  2016年   26篇
  2015年   48篇
  2014年   56篇
  2013年   69篇
  2012年   103篇
  2011年   101篇
  2010年   67篇
  2009年   60篇
  2008年   82篇
  2007年   90篇
  2006年   91篇
  2005年   71篇
  2004年   68篇
  2003年   90篇
  2002年   80篇
  2001年   36篇
  2000年   26篇
  1999年   28篇
  1998年   18篇
  1997年   14篇
  1996年   5篇
  1995年   6篇
  1994年   5篇
  1993年   9篇
  1992年   19篇
  1991年   12篇
  1990年   13篇
  1989年   11篇
  1988年   9篇
  1987年   8篇
  1986年   8篇
  1984年   5篇
  1983年   4篇
  1982年   3篇
  1981年   3篇
  1980年   4篇
  1979年   5篇
  1977年   5篇
  1974年   5篇
  1973年   5篇
  1972年   4篇
  1967年   5篇
  1966年   5篇
排序方式: 共有1566条查询结果,搜索用时 234 毫秒
1.
2.
3.
4.
In their recent review article, Tanvetyanon and Stiff [1] pointedout that hypocalcemia is a frequent side-effect of intravenousbisphosphonates. This adverse event is usually mild and exceptionallysymptomatic, with the principle risk factors being pre-existinghypovitaminosis D, previous parathyroid surgery and intestinalresections. A direct consequence of hypocalcemia  相似文献   
5.
Objective: Increased dimension of the aortic root and proximal aorta is considered a significant risk factor for catastrophic events that involve the ascending aorta. The objective of this study was to determine the possible correlation between pre-dissection aortic diameter and the occurrence of Stanford type A aortic dissection. Methods: Samples of dissected ascending aortas were obtained from 220 patients at the time of their operation. Two groups were identified: patients with connective tissue disorders (Group 1, n = 94) and those without (Group 2, n = 126). Measurements of the true (intimal) lumen were conducted and extrapolated as reliable approximation of pre-dissection aortic diameter. The possible association of intimal diameter with anthropometric and demographic data was analyzed. Results: Median aortic diameter was, respectively, 41.8 and 41.3 mm for patients with and without connective tissue disorders (41.4 mm for the entire cohort). Data analysis indicated that 57% of patients had aortic diameter above 40 mm, while patients with frank aneurysm accounted only for 10%; this proportion was higher in Group 1 compared to Group 2 (17.2% vs 4.7%). Poor or no correlation was demonstrated between aortic size and any of the anthropometric or demographic variables essayed. Significant subgroup differences were found among patients with a history of cigarette smoking, hypertension, diabetes, chronic renal insufficiency, and bicuspid aortic valve. Conclusion: Although aortic diameter remains a strong indication for preventive surgery in patients with inherited connective tissue disorders, acute aortic dissection occurs rarely in the setting of true ascending aortic aneurysms, and despite normal or near-normal aortic size in more than one-third of subjects. Dissection superimposing on small aortic diameters can be regarded as an expression of substantial functional tissue susceptibility to aortic catastrophic events.  相似文献   
6.
Involvement of the temporal bone by lymphoreticular neoplasm is rare; all reported cases have been of secondary involvement. This article presents what we believe to be the first two reported cases of primary temporal bone lymphoma. The patients, an elderly man and a boy, both presented with infection of the ear, hearing loss, and facial nerve paresis. In both cases, facial paresis resolved after appropriate chemotherapeutic treatment. Patient presentation and clinical course are discussed in light of published work on temporal bone malignancy. Further investigation, including computed tomography and biopsy, should be considered for patients who present with an apparent middle ear infection unresponsive to medical therapy. The development of facial paralysis in such a patient warrants heightened suspicion of malignancy.  相似文献   
7.
Haemophilus influenzae type b (Hib) pili are complex filamentous surface structures consisting predominantly of pilin protein subunits. The gene encoding the major pilin protein subunit of Hib adherence pili has been cloned and its nucleotide sequence has been determined. In order to identify specific accessory genes involved in pilus expression and assembly, we constructed isogenic Hib mutants containing insertional chromosomal mutations in the DNA flanking the pilin structural gene. These mutants were screened for pilin production, pilus expression, and hemagglutination. Pili and pilin production were assessed by immunoassays with polyclonal antisera specific for pilin and pili of Hib strain Eagan. Hemagglutination was semiquantitatively evaluated in a microtiter plate assay. Six Hib mutants produced proteins immunoreactive with antipilin antiserum but no longer produced structures reactive with antipilus antiserum. In addition, the mutants were unable to agglutinate human erythrocytes. Nucleotide sequence analysis localized the insertion sites in the six mutants to 2.5-kb open reading frame upstream of the pilin structural gene and immediately downstream of an Hib pilin chaperone gene. The amino acid sequence encoded by this open reading frame has significant homology to members of the pilus assembly platform protein family, including FhaA of Bordetella pertussis, MrkC of Klebsiella pneumoniae, and the Escherichia coli assembly platform proteins FimD and PapC. This open reading frame, designated hifC, appears to represent a gene essential to Hib pilus biogenesis that has genetic and functional similarity to the pilus platform assembly genes of other gram-negative rods.  相似文献   
8.
9.
We documented the presence of lymphocytic prostatitis in all prostate specimens received over a 4-month period. Lymphocytic prostatitis was present in 44% of biopsy specimens (n = 77), 95% of transurethral prostatic resection specimens (n = 20), and 100% of total prostatectomy specimens (n = 9). The patchiness of the prostatitis within the prostate in part explains the lower prevalence in the biopsy specimens, which sample a much smaller portion of the gland compared with the other procedures. Lymphocytic prostatitis was seen in prostates both with and without adenocarcinoma. However, in specimens containing carcinoma, the lymphocytic aggregates rarely involved malignant glands. Instead, the aggregates were either stromal or involved nonmalignant glands either adjacent to or away from the tumor, including glands with hyperplasia, atrophy, and prostatic intraepithelial neoplasia. Even when malignant and nonmalignant glands were in close proximity, there was a sharp demarcation with respect to lymphocytic inflammation. Immunohistochemical staining with B-cell and T-cell markers disclosed that the vast majority are T lymphocytes. The localization of lymphoid aggregates to nonmalignant (including prostatic intraepithelial neoplasia) glands but not frankly neoplastic glands, suggests a selective escape of immune detection by neoplastic glands.  相似文献   
10.
Abstract Closed suction drainage systems are commonly used in orthopaedic surgery, particularly in joint arthroplasty. The rationale for the use of drains is a theoretical reduction of wound haematomas and infection. However the benefit of using drains after total hip or knee arthroplasty is controversial. Several reports have shown that the use of drains does not reduce infection and morbidity and is an unnecessary and potentially dangerous practice. In fact most studies highlighted that at best their use appears to make no difference to important clinical outcomes. Recently a metaanalysis raised the question about the usefulness of closed suction drainage again, concluding that it has no major benefits. The purpose of this study was to review the evidences available concerning the utility of closed suction drainage outlining that this practice is not supported by clinical evidence.  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