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   1359篇
  免费   58篇
  国内免费   33篇
耳鼻咽喉   26篇
儿科学   63篇
妇产科学   19篇
基础医学   112篇
口腔科学   27篇
临床医学   132篇
内科学   367篇
皮肤病学   110篇
神经病学   35篇
特种医学   211篇
外科学   128篇
综合类   30篇
预防医学   80篇
眼科学   9篇
药学   37篇
中国医学   3篇
肿瘤学   61篇
  2019年   9篇
  2018年   7篇
  2017年   12篇
  2016年   16篇
  2015年   22篇
  2014年   25篇
  2013年   68篇
  2012年   14篇
  2011年   16篇
  2010年   49篇
  2009年   58篇
  2008年   21篇
  2007年   31篇
  2006年   29篇
  2005年   31篇
  2004年   16篇
  2003年   12篇
  2002年   23篇
  2001年   21篇
  2000年   16篇
  1999年   21篇
  1998年   83篇
  1997年   72篇
  1996年   76篇
  1995年   51篇
  1994年   64篇
  1993年   52篇
  1992年   16篇
  1991年   18篇
  1990年   23篇
  1989年   48篇
  1988年   45篇
  1987年   39篇
  1986年   26篇
  1985年   29篇
  1984年   25篇
  1983年   13篇
  1982年   23篇
  1981年   18篇
  1980年   14篇
  1979年   19篇
  1978年   15篇
  1977年   16篇
  1976年   16篇
  1975年   12篇
  1973年   14篇
  1972年   10篇
  1971年   7篇
  1965年   6篇
  1957年   7篇
排序方式: 共有1450条查询结果,搜索用时 15 毫秒
51.
52.
53.
Parent‐of‐origin–dependent (epi)genetic factors are important determinants of prenatal development that program adult phenotype. However, data on magnitude and specificity of maternal and paternal genome effects on fetal bone are lacking. We used an outbred bovine model to dissect and quantify effects of parental genomes, fetal sex, and nongenetic maternal effects on the fetal skeleton and analyzed phenotypic and molecular relationships between fetal muscle and bone. Analysis of 51 bone morphometric and weight parameters from 72 fetuses recovered at day 153 gestation (54% term) identified six principal components (PC1–6) that explained 80% of the variation in skeletal parameters. Parental genomes accounted for most of the variation in bone wet weight (PC1, 72.1%), limb ossification (PC2, 99.8%), flat bone size (PC4, 99.7%), and axial skeletal growth (PC5, 96.9%). Limb length showed lesser effects of parental genomes (PC3, 40.8%) and a significant nongenetic maternal effect (gestational weight gain, 29%). Fetal sex affected bone wet weight (PC1, p < 0.0001) and limb length (PC3, p < 0.05). Partitioning of variation explained by parental genomes revealed strong maternal genome effects on bone wet weight (74.1%, p < 0.0001) and axial skeletal growth (93.5%, p < 0.001), whereas paternal genome controlled limb ossification (95.1%, p < 0.0001). Histomorphometric data revealed strong maternal genome effects on growth plate height (98.6%, p < 0.0001) and trabecular thickness (85.5%, p < 0.0001) in distal femur. Parental genome effects on fetal bone were mirrored by maternal genome effects on fetal serum 25‐hydroxyvitamin D (96.9%, p < 0.001) and paternal genome effects on alkaline phosphatase (90.0%, p < 0.001) and their correlations with maternally controlled bone wet weight and paternally controlled limb ossification, respectively. Bone wet weight and flat bone size correlated positively with muscle weight (r = 0.84 and 0.77, p < 0.0001) and negatively with muscle H19 expression (r = –0.34 and –0.31, p < 0.01). Because imprinted maternally expressed H19 regulates growth factors by miRNA interference, this suggests muscle‐bone interaction via epigenetic factors. © 2014 American Society for Bone and Mineral Research.  相似文献   
54.
55.
Ileocecal Tuberculosis   总被引:1,自引:0,他引:1  
Three cases of ileocecal tuberculosis are presented with a review of pathogenesis, diagnosis and therapy.
Emphasis is placed upon preoperative suspicion and the indications for resectional surgery in combination with antituberculous drugs in the management of the patients.  相似文献   
56.
Blood transfusion and postoperative infection in orthopedic patients   总被引:9,自引:0,他引:9  
Adverse effects of the transfusion of homologous blood on tumor recurrence and resistance to bacterial infection have been reported previously, but the findings are inconclusive. A retrospective review of patients undergoing orthopedic surgery was conducted, and the rate of the postoperative infectious complications was compared among those receiving homologous blood, autologous blood, both types, or no transfusion support. An overall postoperative infection rate of 6.1 percent was observed: 6.9 percent among persons receiving homologous blood, 5.0 percent among those receiving autologous blood, 11.9 percent among those receiving both homologous and autologous blood, and 4.9 percent among those not receiving transfusions (p = 0.37). Among patients receiving homologous blood, a subset of 15 patients received homologous whole blood and had an infection rate of 20 percent. Significant predictors of postoperative infection included increasing age, spinal surgery, high admission hematocrit, and greater time in surgery. Of factors relating to transfusion, only the use of homologous whole blood was a significant predictor of postoperative infection, which suggests a detrimental effect of homologous plasma. It can be concluded that, in this group of patients undergoing relatively nontraumatic surgery, several variables that are not related to transfusion, as well as the use of homologous whole blood, were significant predictors of postoperative infection.  相似文献   
57.
Summary 1. Twenty-two patients with infectious mononucleosis were studied by liver biopsy and paper electrophoresis of the serum proteins. The findings were compared with a similar group of 30 patients with infectious hepatitis.2. The essential histologic features of infectious mononucleosis were the presence in the hepatic sinusoids and portal tracts of chronic inflammatory cells resembling small lymphocytes, with essentially no parenchymal cell damage. Admixed with this lymphocytic infiltrate, but in relatively minimal numbers, were a few plasma cells and polymorphonuclear leukocytes. In addition, in infectious mononucleosis there were, with rare exceptions, no lipochrome-containing Kupffer cells. Thus, in the majority of cases, the histologic picture was distinct from that seen in infectious hepatitis. Only in comparing a few of the more severe infectious mononucleosis cases with subsiding infectious hepatitis cases was there any tendency for the two pictures to merge, and the distinction on histologic grounds between the two entities could be made in the great majority of cases.3. The most commonly seen abnormalities in the paper electrophoretic patterns of sera obtained from patients with infectious mononucleosis were decreased albumin, increased gamma globulin, not infrequent but variable changes in alpha2 globulin, and the presence of abnormal proteins migrating with mobilities intermediate to alpha2 and beta, and beta and gamma globulins. The abnormalities observed in infectious hepatitis were similar to those of infectious mononucleosis, except that in hepatitis alpha2 globulin was decreased more consistently, gamma globulin increased less frequently, and beta globulin, which was normal in practically all the cases of infectious mononucleosis, was increased in a considerable number of cases.4. Treatment of patients with infectious mononucleosis need not include prolonged bed rest and restriction of activity in an effort to avoid the development of chronic liver disease.  相似文献   
58.
Summary The management of pilonidal cyst disease in a large military hospital is described. Of special interest to the military practice is the “buddy” system, in which patients help one another to keep their wounds clean and dry. The specific objectives of our technic are: 1) obtaining excellent hemostasis by the use of zinc peroxide paste; 2) avoiding recurrences by an open-wound method of treatment; 3) preservation of a pad of subcutaneous tissue over the postsacral fascia, thus reducing long-term morbidity by insuring a mobile scar; 4) decreasing the duration of hospitalization, achieved by frequently drying the wounds with warm air. Read at the meeting of the American Proctologic Society, Hollywood, Florida, April 12 to 16, 1970. The opinions or assertions contained herein are those of the authors and are not to be construed as official or as reflecting the views of the Navy Department.  相似文献   
59.
To evaluate the potential of laser-induced fluorescence spectroscopy for the detection of premalignant lesions of the gastrointestinal tract, the hypothesis that adenomatous transformation of colonic mucosa results in an alteration of laser-induced fluorescence that enables its differentiation from normal or hyperplastic tissue was tested. A fiberoptic catheter coupled to a helium-cadmium laser (325 nm) and an optical multichannel analyzer were used to obtain fluorescence spectra (350-600 nm) from 35 normal colonic specimens and 35 resected adenomatous polyps. A score based on six wavelengths was derived by stepwise multivariate linear regression analysis of the spectra. The mean score (+/- SEM) was + 0.86 +/- 0.06 for normal mucosa and -0.86 +/- 0.06 for adenomatous polyps (P less than 0.001). Spectra from an additional 34 normal specimens, 16 adenomatous polyps, and 16 hyperplastic polyps were prospectively classified with accuracies of 100%, 100%, and 94%, respectively. The mean score for hyperplastic polyps was significantly different from adenomatous (P less than 0.001) but not from normal tissue. Thus, quantitative analysis of fluorescence spectra enables the detection of adenomatous transformation in colonic mucosa.  相似文献   
60.
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