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   1514篇
  免费   97篇
  国内免费   22篇
耳鼻咽喉   18篇
儿科学   69篇
妇产科学   14篇
基础医学   285篇
口腔科学   24篇
临床医学   135篇
内科学   278篇
皮肤病学   87篇
神经病学   159篇
特种医学   55篇
外科学   189篇
综合类   6篇
预防医学   84篇
眼科学   16篇
药学   65篇
肿瘤学   149篇
  2023年   10篇
  2022年   22篇
  2021年   41篇
  2020年   22篇
  2019年   26篇
  2018年   39篇
  2017年   25篇
  2016年   31篇
  2015年   39篇
  2014年   42篇
  2013年   64篇
  2012年   108篇
  2011年   116篇
  2010年   84篇
  2009年   81篇
  2008年   125篇
  2007年   99篇
  2006年   121篇
  2005年   78篇
  2004年   83篇
  2003年   80篇
  2002年   80篇
  2001年   21篇
  2000年   13篇
  1999年   21篇
  1998年   18篇
  1997年   8篇
  1996年   9篇
  1995年   6篇
  1994年   13篇
  1993年   12篇
  1992年   8篇
  1991年   7篇
  1990年   7篇
  1988年   3篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1982年   5篇
  1981年   6篇
  1980年   8篇
  1979年   4篇
  1978年   6篇
  1977年   4篇
  1976年   3篇
  1975年   2篇
  1974年   4篇
  1973年   3篇
  1972年   5篇
  1966年   2篇
排序方式: 共有1633条查询结果,搜索用时 15 毫秒
11.
Amphiphysin is a protein peripherally associated with synapticvesicles. It is expressed in many neurons, certain endocrinecell types, and spermatocytes. Autoantibodies against amphiphysinoccur in patients afflicted with a rare neurologic autoimmunedisease, paraneoplastic Stiff—Man syndrome. To providea basis for the understanding of antl-amphiphysin autolmmunity,we have cloned cDNAs and determined the primary structure ofhuman amphiphysin. Comparison with chicken amphiphysin definesdomains of low and high amino acid sequence conservation. Asa candidate for heritable disorders of the nervous system, endocrinetissues or male fertility, the human amphiphysin gene was mappedto chromosome 7, region p13–p14.  相似文献   
12.
The last decade has witnessed increasing application of human cytogenetic technology to prenatal chromosome analysis. However, unlike the rather uniform peripheral blood T-lymphocyte system which has provided most of our experience in human cytogenetics, long-term amniotic-fluid cell cultures display extreme cellular heterogeneity and disproportionate growth of certain cell types as a consequence of clonal amplification. When they enter cell culture, many of these cells are approching the terminal stages of their respective life spans and may have accumulated chromosomal aberrations. Concern about the possibility of true fetal mosaicism seems warranted chiefly in situations were multiple colonies display potentially viable aberrations. Clonal analysis, preferable of multiple clonal types, and attention to details of clonal morphology are likely to minimize diagnostic errors and undue apprehension resulting from mosaicism in amniotic-fluid cell cultures.  相似文献   
13.
The role of del (11)(p13) as a cause of aniridia, with and without Wilms tumor, is strengthened by demonstration of this chromosome aberration in 3 patients: monozygous twin girls, both of whom have aniridia and mental retardation and one of whom has a Wilms tumor; and an unrelated boy with aniridia and ambiguous genitalia. The break points defining the interstitial deletion for the twins are 11p13 and 11p15.1, while for the boy they are 11p1302 and 11p14.1. These patients and their karyotypes substantiate the critical importance of chromosome band 11p13 (or its hemizygous representation) in the development of aniridia and an associated Wilms tumor diathesis, as had been suggested previously (Riccardi VM, Sujansky E, Smith AC, Francke U, (1978): Pediatrics 61, 604-610).  相似文献   
14.
We have studied 4 patients with inverted tandem duplications of parts of chromosomes, a hitherto rarely identified from of a structural rearrangement involving a single chromosome in man. In Patients 1 and 2, the duplication involved parts of the short arm of chromosome 8 (regions 8p 12→8p23 and 8p21→8p23, respectively). Both patients manifested certain characteristics of the mosaic trisomy 8 syndrome. Elevated levels of glutathione reductase (GSR) in their erythrocytes supported the interpretation of a partial duplication of chromosome 8 and indicated a regional localization for the GSR gene locus. In Patient 3, the distal half of the long arm of chromosome 4 was duplicated (region4q26→4q35). Clinical evidence supported this interpretation, as Patient 3 resembled phenotypically the 13 reported cases with duplication of the distal 4q. The cytogenetic findings in Patient 4 suggested a possibly inverted duplication of 22q. The clinical correlation was less convincing due to the lack of a well-defined phenotype for trisomy 22. These chromosome aberrations had occurred de novo in all 4 cases. Although they involved different chromosomal regions, they might well have arisen by the same mechanism. Possible modes of origin that are discussed in detail include unequal exchange between homologous chromosomes, between chromatids of 1 chromosome or between strands of 1 DNA duplex.  相似文献   
15.
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Die COVID-19-Pandemie hat den beruflichen Alltag von Lehrpersonal erheblich verändert. Das Ziel dieser Arbeit ist es, die...  相似文献   
16.
17.
ObjectiveTo summarize the effects of routine, opt-out abortion and family planning residency training on obstetrics and gynecology (ob-gyn) residents’ clinical skills in uterine evacuation and intentions to provide abortion care after residency.MethodsData from ob-gyn residency programs supported during the first 20 years of the Kenneth J. Ryan Residency Training Program in Abortion and Family Planning were analyzed. Postrotation surveys assessed residents’ training experiences and acquisition of abortion care skills. Residency program director surveys assessed benefits of the training to residents and the academic department from the educators’ perspectives.ResultsA total of 2775 residents in 89 ob-gyn programs completed postrotation surveys for a response rate of 72%. During the rotation, residents – including those who only partially participated – gained exposure to and skills in first- and second-trimester abortion care. Sixty-one percent intended to provide abortion care in their postresidency practice. More than 90% of residency program directors (97.5% response rate) reported that training improved resident competence in abortion and contraception care and 81.3% reported that the training increased their own program's appeal to residency applicants.ConclusionOver 20 years, the Ryan Program has supported programs to integrate abortion training to give ob-gyn residents the skills and inspiration to provide comprehensive reproductive health care, including uterine evacuation and abortion care, in future practice. Residency program directors noted that this integrated training meets resident applicants’ expectations.ImplicationsRyan Program residents are trained to competence and are prepared, both clinically and in their professional attitudes, to care for women's reproductive health.  相似文献   
18.
A spinal synovial cyst is a rare condition. We reported a case of lumbar spinal synovial cyst presenting neurological deficit. A 78-year-old woman was admitted to our hospital with the low back pain radiating to the left buttock. A myelography with computed tomography and magnetic resonance imaging revealed an extradural cystic lesion at the L5 and S1 level. At the time of surgery, a standard posterior approach was used to expose the posterior elements from L5 to S1. An en bloc laminectomy and total removal of the cyst was performed at the L5 to S1 level. The postoperative recovery was uneventful except for a slight pain in the left leg which persisted for some time.  相似文献   
19.
20.
PURPOSE: Survivin is a member of the inhibitor-of-apoptosis gene family and is known to be overexpressed in a number of tumor types. The aim of this study was to evaluate the prognostic value of survivin protein expression in tumor tissue extracts in a group of well-characterized soft-tissue sarcoma (STS) patients. EXPERIMENTAL DESIGN: In this investigation, malignant tissue samples from 63 STS patients as well as from a panel of tumor cell lines were investigated, with nonmalignant tissues serving as controls. The survivin protein level was quantified by a novel ELISA and by Western blot analysis. Results obtained by both methods were compared with clinicopathological parameters regarding tumor grade and tumor entity, and they were then correlated to survival in a multivariate Cox regression model. RESULTS: High survivin levels were detected by ELISA and Western blot analysis in tumor tissue extracts and in lysates of tumor cell lines. None or only weak expression of survivin protein was found in nonmalignant cells and tissues. When comparing survivin values obtained by ELISA or Western blot, we found a significant correlation between both methods (P = 0.013, Pearson test). Our findings revealed that, in multivariate Cox regression analyses, survivin levels measured by ELISA and Western blot were significantly associated with tumor-related death in STS patients (P = 0.001, RR = 19.8, and P = 0.004, RR = 5.1, respectively). However, in a direct comparison of both survivin protein detection assays, we found a higher sensitivity and a stronger correlation to prognosis in survivin ELISA as compared with the Western blot assays. Furthermore, a higher tumor grade and more aggressive STS entity showed an elevated survivin protein expression level. CONCLUSION: Altogether, an elevated survivin content in tumor tissue extracts has a significant and independent negative predictive value on the survival-rate of STS patients. This finding corresponds well to data obtained for the mRNA level of survivin, as shown previously (M. Kappler et al., Int. J. Cancer, 95: 360-363, 2001).  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