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   321篇
  免费   23篇
  国内免费   3篇
耳鼻咽喉   5篇
儿科学   9篇
妇产科学   1篇
基础医学   49篇
口腔科学   5篇
临床医学   32篇
内科学   63篇
皮肤病学   6篇
神经病学   10篇
特种医学   19篇
外科学   39篇
综合类   5篇
预防医学   26篇
眼科学   18篇
药学   36篇
中国医学   6篇
肿瘤学   18篇
  2023年   3篇
  2022年   6篇
  2021年   15篇
  2020年   8篇
  2019年   13篇
  2018年   21篇
  2017年   4篇
  2016年   13篇
  2015年   9篇
  2014年   10篇
  2013年   15篇
  2012年   29篇
  2011年   21篇
  2010年   13篇
  2009年   6篇
  2008年   11篇
  2007年   18篇
  2006年   17篇
  2005年   10篇
  2004年   12篇
  2003年   26篇
  2002年   8篇
  2001年   4篇
  2000年   4篇
  1999年   3篇
  1998年   2篇
  1995年   2篇
  1993年   5篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1984年   1篇
  1983年   4篇
  1982年   2篇
  1981年   2篇
  1978年   4篇
  1976年   1篇
  1974年   1篇
  1971年   3篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   2篇
  1965年   1篇
  1933年   1篇
  1930年   1篇
  1923年   1篇
排序方式: 共有347条查询结果,搜索用时 15 毫秒
1.
The treatment of Legg-Calvé-Perthes disease remains controversial. The aim of this survey was to ascertain the current management strategies of this condition amongst UK paediatric orthopaedic surgeons, with particular regard to containment procedures in the fragmentation phase. Questionnaires were distributed at the January 2006 meeting of the British Society for Children’s Orthopaedic Surgery (BSCOS) and was posted to all absent members. The results showed a great deal of variability not only in the treatment of Perthes disease, but also in the decision-making processes. Consideration must now be given to a carefully constructed national multi-centre prospective randomised controlled study into the optimum management of this disease  相似文献   
2.
Parallel to the inactivation of the X chromosome in somatic cells of female, the male X in mammals is rendered inactive during spermatogenesis. Pseudoautosomal genes, those present on the X-Y meiotically pairable region of male, escape inactivation in female soma. It is suggested, but not demonstrated, that they may also be refractory to the inactivation signal in male germ cells. We have assayed activity of the enzyme steroid sulfatase, product of a pseudoautosomal gene, in testicular cells of the mouse and shown its presence in premeiotic, meiotic (pachytene), and postmeiotic (spermatid) cell types. It appears that, as in females, pseudoautosomal genes may escape inactivation in male germ cells also.  相似文献   
3.
We describe the molecular analysis of three families with hypodontia involving primarily molar teeth and report two novel mutational mechanisms. Linkage analysis of two large families revealed that the hypodontia was linked to the PAX9 locus. These two families revealed missense mutations consisting of a glutamic acid substitution for lysine and a proline substitution for leucine within the paired domain of PAX9. A pair of identical twins affected with hypodontia in a third family demonstrated a 288-bp insertion within exon 2 that resulted in a putative frameshift mutation and a premature stop codon. The insertion was associated with the loss of 7-bp from exon 2. A block of 256-bp of sequence within the insertion was completely identical to downstream sequence from the second intron of the PAX9 gene. These studies extend the spectrum of mutations in PAX9 associated with hypodontia to include heretofore undescribed categories, including missense mutations.  相似文献   
4.
Annamalai P  Rao AL 《Virology》2005,338(1):96-111
To begin elucidation of the relationship between Brome mosaic virus (BMV) replication and encapsidation, we used a T-DNA-based Agrobacterium-mediated transient expression (agroinfiltration) system in Nicotiana benthamiana leaves to express either individual or desired pairs of the three genomic RNAs. The packaging competence of these RNAs into virions formed by the transiently expressed coat protein (CP) was analyzed. We found that in the absence of a functional replicase, assembled virions contained non-replicating viral RNAs (RNA1 or RNA2 or RNA3 or RNA1 + RNA3 or RNA2 + RNA3) as well as cellular RNAs. By contrast, virions assembled in the presence of a functional replicase contained only viral RNAs. To further elucidate the specificity exhibited by the functional viral replicase in RNA packaging, replication-defective RNA1 and RNA2 were constructed by deleting the 3' tRNA-like structure (3' TLS). Co-expression of TLS-less RNA1 and RNA2 with wt RNA3 resulted in efficient synthesis of subgenomic RNA4. Virions recovered from leaves co-expressing TLS-less RNA1 and RNA2 and either CP mRNA or wt RNA3 exclusively contained viral RNAs. These results demonstrated that packaging of BMV genomic RNAs is not replication dependent whereas expression of a functional viral replicase plays an active role in increasing specificity of RNA packaging.  相似文献   
5.
Obstructive jaundice was produced in rats by ligation and transection of bile duct outside the liver; the control group underwent laparotomy alone. Pancreatic wet weight, amylase, lipase, protein, DNA, RNA, RNA/DNA ratio, and weight/100 g DNA were significantly increased in jaundiced rats when compared to control rats. Histologic evaluation of pancreatic tissue obtained from jaundiced rats revealed the appearance of large or multiple nuclei in pancreatic acinar cells. Basal plasma levels of immunoreactive CCK were significantly increased in haundiced rats at two weeks and four weeks but, when compared to the levels obtained in laparotomized controls at those time intervals, CCK levels were not significantly different. In jaundiced rats, plasma immunoreactive gastrin was found to be significantly decreased at two and four weeks. Plasma gastrin levels were also found significantly decreased when the jaundiced group was compared with laparotomized control group. The results suggest that obstructive jaundice induced enlargement of the pancreas, probably due to hyperplasia and hypertrophy of pancreatic cells. Whether or not this phenomenon is related to changes in gastrin and CCK is not known.This work was presented in part at the 36th Kinki Section Meeting of Japanese Gastroenterological Association (January 1982) in Osaka, Japan; at the Annual Meeting of the Japanese Pancreatic Association (March 1982) in Hiroshima, Japan; and at the American Gastroenterological Association (May 1983) in Washington, D.C.; and appeared in abstract form inGastroenterology 84: 1095, 1983.  相似文献   
6.
Congenital constriction band syndrome has varied clinical presentations ranging from small, incomplete skin deep constriction band to in utero amputation. Pseudarthrosis of underlying bone most commonly tibia has been reported by many authors. We report the first case of congenital pseudarthrosis of the femur with congenital constriction band syndrome. Nine-day-old female presented with the constriction band in the left thigh with open pseudarthrosis of the femur. The left femur had gross recurvatum deformity and the posterior apex of the pseudarthrosis was exposed via skin ulceration. She had an ipsilateral paralytic clubfoot. She was treated with single-stage excision of constriction band and Z-plasty. Spontaneous union of the femur was achieved at 3 months. Procurvatum deformity of the femur improved gradually over 3 years. This happens to be the first and only reported case of congenital pseudarthrosis of the femur with sciatic nerve palsy due to congenital constriction band.  相似文献   
7.
We measured cytokine secretion patterns in peripheral blood and granulation tissue by flow cytometry in 16 human immunodeficiency virus (HIV) positive and 26 HIV negative patients with spinal tuberculosis. Anti-retroviral therapy was not prescribed. There were no significant differences in the postoperative morbidity and neurological recovery between the two groups.
Résumé Nous avons mesuré, par cytométrie en flux, la sécrétion de cytokine dans le sang périphérique et le tissu de granulation chez des patients atteints de tuberculose rachidienne, 16 HIV positifs et 26 HIV négatifs. Il n’y avait pas de différence significative dans la morbidité post-opératoire et la récupération neurologique entre les deux groupes.


Accepted: 21 February 2000  相似文献   
8.
9.
A 12- week feeding trial was conducted to determine the effects of dietary vitamin C levels on the growth performance, antioxidant ability, muscle composition and enzyme activity in freshwater prawn, Macrobrachium rosenbergii. The experimental basal diets were supplemented with M. rosenbergii at the rates of 0 (control), 25, 50, 75, 150 and 300 mg/kg dry feed weight and the assays were in triplicate. Growth performance, body composition, antioxidant activity and serum biochemistry parameters were determined. However, the present investigation revealed that prawns fed with diet supplemented with 25–150 mg/kg of vitamins C shows enhanced (P < 0.05) growth performance, including final weight and weight gain. Additionally, prawns fed with 25–150 mg/kg of vitamins C supplemented diets achieved significant (P < 0.05) improvement in growth performance, digestive enzyme activities, and muscle biochemical composition, while, the prawns fed with 150 mg/kg of vitamin C showed enhanced performance respectively. However, the prawns fed with above 150–300 mg/kg showed poor performance. The antioxidant enzymatic activity (SOD, CAT) metabolic enzyme status in muscle showed no significant (P > 0.05) alterations in prawns fed with 25–150 mg/kg of vitamin C supplemented diets. Therefore, the present findings suggested that 150 mg/kg of vitamin C could be supplemented for flexible enhanced survival, growth, antioxidant defense system and production of M. rosenbergii.  相似文献   
10.
An investigation was carried out in an organized dairy farm of Tamil Nadu State, India where cattle were reported to have eye infection. Preliminary clinical intervention revealed that the animals had infectious bovine keratoconjunctivitis (IBK). Isolation and identification of pathogen from eye swab revealed the presence of Moraxella spp. On further molecular characterization by Polymerase chain reaction (PCR) suggested that the isolate as Moraxella bovoculi. PCR followed by sequencing was carried and the results showed that the isolate was M. bovoculi and the sequence was submitted in the GenBank with the sequence id. KX121047. Animals were treated with antibiotics as per the results from antibiotic sensitivity test and treatment yielded good results as the animals responded to treatment. This report is the first of its kind from India as there was no previous report regarding M. bovoculi from the country. Further insights into the bacterial genome can aid in identification of the genes or regions involved in pathogenesis of IBK and also to carve out the prevention and control strategies of IBK.  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