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   1604篇
  免费   62篇
  国内免费   33篇
耳鼻咽喉   29篇
儿科学   88篇
妇产科学   23篇
基础医学   160篇
口腔科学   36篇
临床医学   133篇
内科学   414篇
皮肤病学   114篇
神经病学   101篇
特种医学   221篇
外国民族医学   1篇
外科学   146篇
综合类   31篇
预防医学   83篇
眼科学   12篇
药学   54篇
中国医学   3篇
肿瘤学   50篇
  2019年   10篇
  2017年   13篇
  2016年   17篇
  2015年   23篇
  2014年   30篇
  2013年   71篇
  2012年   21篇
  2011年   20篇
  2010年   51篇
  2009年   62篇
  2008年   26篇
  2007年   36篇
  2006年   36篇
  2005年   40篇
  2004年   19篇
  2003年   22篇
  2002年   31篇
  2001年   36篇
  2000年   27篇
  1999年   33篇
  1998年   87篇
  1997年   74篇
  1996年   77篇
  1995年   51篇
  1994年   62篇
  1993年   54篇
  1992年   27篇
  1991年   29篇
  1990年   33篇
  1989年   52篇
  1988年   55篇
  1987年   46篇
  1986年   35篇
  1985年   35篇
  1984年   34篇
  1983年   18篇
  1982年   28篇
  1981年   20篇
  1980年   18篇
  1979年   19篇
  1978年   14篇
  1977年   18篇
  1976年   22篇
  1975年   15篇
  1974年   11篇
  1973年   16篇
  1972年   13篇
  1971年   11篇
  1970年   8篇
  1968年   8篇
排序方式: 共有1699条查询结果,搜索用时 31 毫秒
21.
22.
23.
McLellan  GL; Scalapino  MC 《Radiology》1988,169(1):264-265
A modified technique for catheterization of the pulmonary artery was developed. It involves the passage of a tapered, movable-core, J-tipped guide wire across the right ventricle into the pulmonary artery followed by the advancement of a straightened Grollman pigtail catheter. The technique was successful in 34 of 34 pulmonary artery catheterizations. The method avoids prolonged catheter manipulation within the right ventricle. In addition, since the catheter does not cross the tricuspid valve until the guide wire has been advanced, the occasional complication of the pigtail "hooking" on a tricuspid valve leaflet or chordae tendineae during catheter withdrawal and manipulation is prevented.  相似文献   
24.
This study reviews the demographic, radiologic, and histologic characteristics of 13 cases of an important primary skeletal neoplasm, giant cell tumor of bone, occurring in an uncommon location, the scapula. that eight of 13 patients presented prior to 20 years of age contrasts significantly with the typical age distribution (between 20–40 years) encountered in giant cell tumors arising in long bones. As it does elsewhere in the skeleton, giant cell tumor of the scapula frequently demonstrates cystic and/or telangiectatic components on histologic examination. The radiologic appearances of giant cell tumor in the scapula and in more typical locations are similar and include: (1) well-defined (geographic) margins, occasionally with a delicate sclerotic rim, (2) prominent trabeculations, (3) expanded bone contour, (4) frequent extension to the subchondral plate, and (5) absence of internal mineralization. Tumor sites within the scapula included: coracoid process, acromion, and body (three cases each); glenoid (two cases); and superior and inferior angles (one case each).The opinions or assertions contained herein are the private views of the authors and are not to be construed as official or as reflecting the views of the Department of the Army, the Department of Defense, or the Uniformed Services University of the Health Sciences.  相似文献   
25.
The effect of lateral amygdala or stria terminalis lesions on two different kinds of aggressive behavior have been studied in the rat. The lateral amygdala lesion does not change the non-killing rat's behavior towards mice; but it markedly reduces the shock-induced intraspecific aggression, without changing the flinch and jump thresholds to the electric shocks. A bilateral interruption of the stria terminalis elicits aggressive reactions in previously non killing rats. This initiation of mouse killing behavior is clearly facilitated through a prior food deprivation for 3 days. The interruption of the stria terminalis changes neither the shock induced aggression, nor the response thresholds. As the stria is the main efferent pathway of the cortico-medial nuclei of the amygdala, these results are in accordance with previous conclusions that tentatively localized in this part of the amygdala an essential component of a mechanism which inhibits muricide behavior in the non killing rat, probably through interactions with the olfactory input. This system is largely independent of amygdaloid structures which facilitate shock-induced intraspecific aggression.  相似文献   
26.
Recombination of deltaRec to psiJalpha will delete the TCR delta gene, which is thought to play an important role in the bifurcation of the TCR alphabeta versus TCR gammadelta differentiation lineages. We recently detected a DNA-binding protein in human thymocytes, the so- called PJA-BP, which recognizes the psiJalpha gene segment and might be one of the factors involved in the regulation of preferential deltaRec- psiJalpha rearrangements. We now investigate PJA-BP expression and its correlation with TCR delta gene deletion in thymocytes. Our electrophoretic mobility shift assay experiments showed that the PJA-BP is evolutionary conserved in human, murine and simian thymocytes. Using a large series of human hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is thymocyte specific and seems to be restricted to thymocytes committed to the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte subpopulations showed that preferential deltaRec-psiJalpha rearrangements as well as PJA-BP expression can be detected from the immature CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage onwards. These experiments indicate that expression of PJA-BP in human thymocytes starts simultaneously with preferential deltaRec-psiJalpha rearrangements, which supports our hypothesis that PJA-BP is one of the factors involved in the preferential recombination of deltaRec to psiJalpha.   相似文献   
27.
Long-Evans hooded rats were tested for emotionality and observed by pairs in an open field for 6 consecutive days. Postoperative observations indicated that both emotionality and social cohesiveness were dramatically altered by ventromedial and anterolateral hypothalamic lesions. Tegmental, interpeduncular and habenular lesions were shown to have no effect on these behaviors. Alterations in behavior observed following hypothalamic ablations were related to septal and amygdaloid effects, and the possibility of separate projection systems for emotionality and social cohesiveness was discussed.  相似文献   
28.
29.
The Bethlem myopathy is a rare autosomal dominant proximal myopathy characterized by early childhood onset and joint contractures. Evidence for linkage and genetic heterogeneity has been established, with the majority of families linked to 21q22.3 and one large family linked to 2q37, implicating the three type VI collagen subunit genes, COL6A1 (chromosome 21), COL6A2 (chromosome 21) and COL6A3 (chromosome 2) as candidate genes. Mutations of the invariant glycine residues in the triple-helical domain-coding region of COL6A1 and COL6A2 have been reported previously in the chromosome 21-linked families. We report here the identification of a G-->A mutation in the N-terminal globular domain-coding region of COL6A3 in a large American pedigree (19 affected, 12 unaffected), leading to the substitution of glycine by glutamic acid in the N2 motif, which is homologous to the type A domains of the von Willebrand factor. This mutation segregated to all affected family members, to no unaffected family members, and was not identified in 338 unrelated Caucasian control chromosomes. Thus mutations in either the triple-helical domain or the globular domain of type VI collagen appear to cause Bethlem myopathy.   相似文献   
30.
An allergic reaction following intrauterine insemination   总被引:1,自引:0,他引:1  
Intrauterine insemination is a common procedure used for the treatment of different causes of infertility. Adverse reactions associated with this procedure are very rare and usually the procedure is well tolerated by the patient. We report a case of an allergic reaction after intrauterine insemination. The patient developed fever, difficulty breathing and wheezing in both lung fields. Although a low concentration of penicillin in the medium was used, it caused a significant allergic reaction. When intrauterine insemination was performed in subsequent cycles with an antibiotic-free medium, no allergic reaction occurred, and the procedure was well tolerated by the patient. A careful allergy history is essential in patients pursuing infertility treatment where antibiotics are utilized. Patients who are known to be allergic to penicillin should have semen prepared by an antibiotic-free medium.   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