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   1029篇
  免费   39篇
  国内免费   11篇
耳鼻咽喉   23篇
儿科学   31篇
妇产科学   26篇
基础医学   101篇
口腔科学   101篇
临床医学   81篇
内科学   190篇
皮肤病学   15篇
神经病学   36篇
特种医学   41篇
外科学   212篇
综合类   6篇
预防医学   91篇
眼科学   3篇
药学   52篇
中国医学   3篇
肿瘤学   67篇
  2022年   22篇
  2021年   34篇
  2020年   20篇
  2019年   24篇
  2018年   35篇
  2017年   20篇
  2016年   22篇
  2015年   20篇
  2014年   38篇
  2013年   42篇
  2012年   62篇
  2011年   57篇
  2010年   31篇
  2009年   32篇
  2008年   49篇
  2007年   55篇
  2006年   28篇
  2005年   32篇
  2004年   38篇
  2003年   30篇
  2002年   20篇
  2001年   18篇
  2000年   32篇
  1999年   23篇
  1998年   17篇
  1997年   14篇
  1996年   9篇
  1995年   13篇
  1994年   13篇
  1993年   15篇
  1992年   11篇
  1991年   12篇
  1990年   11篇
  1989年   20篇
  1988年   6篇
  1987年   14篇
  1986年   20篇
  1985年   20篇
  1984年   14篇
  1983年   14篇
  1982年   7篇
  1981年   5篇
  1980年   10篇
  1979年   3篇
  1978年   5篇
  1976年   8篇
  1975年   4篇
  1973年   4篇
  1971年   3篇
  1970年   3篇
排序方式: 共有1079条查询结果,搜索用时 15 毫秒
71.
The authors report on 14 patients with epidermoid carcinoma of the glottic region, classified T1, T2 and T3, operated upon by a hemilaryngectomy (9 cases) with reconstruction using a Plathysma myocutaneous flap. The oncological results over a follow-up period of 1 to 6 years and the functional results are analyzed. The authors conclude that this method does not compromise the carcinological result and provides a good functional result with low ratings for complications, with in addition an adequate support for the organ, favouring increased resections.  相似文献   
72.
Massive hemoptysis: control by embolization of the thyrocervical trunk   总被引:1,自引:0,他引:1  
Moore  LB; McWey  RE; Vujic  I 《Radiology》1986,161(1):173-174
A case of recurrent hemoptysis following bronchial artery embolization is presented. The bleeding was successfully controlled by embolization of the thyrocervical trunk.  相似文献   
73.
74.
3,4-Methylenedioxymethamphetamine (MDMA) is frequently consumed at “rave” parties by polydrug users that usually take this drug in association with ethanol. In addition, many young people are repeatedly exposed to ethanol, which likely leads to tolerance phenomena. Both compounds are metabolized in the liver, with formation of hepatotoxic metabolites, which gives high relevance to the evaluation of their putative toxicological interaction. Therefore, the aim of this study was to evaluate the toxicity induced by 0.8 and 1.6 mM MDMA to freshly isolated hepatocytes obtained from ethanol-treated mice whose tap drinking water was replaced by a 5% ethanol solution for 1 week and, afterwards, by a 12% ethanol solution for 8 weeks (ethanol group) comparatively to non-treated animals (non-ethanol group). The hepatocytes were incubated under normothermic and hyperthermic conditions in order to simulate in vitro the hyperthermic response induced in vivo by MDMA, a condition that has been recognized as a life-threatening effect associated with MDMA exposure and implicated in its hepatotoxicity. Six mice treated under the same protocol as the ethanol group were used for histological analysis, and compared to non-ethanol-treated animals. The pre-treatment of mice with ethanol caused a significant decrease in the hepatocytes yield in the isolation procedure comparatively to the non-ethanol group, which can be explained by an increase in collagen deposition along the hepatic parenchyma as observed in the histological analysis. The initial cell viability of hepatocytes suspensions was similar between ethanol and non-ethanol groups. However, the ethanol group showed a higher GSH oxidation rate, which was enhanced under hyperthermia. Additionally, a concentration-dependent MDMA-induced loss of cell viability and ATP depletion was observed for both groups, at 41 °C. In conclusion, the repeated treatment with ethanol seems to increase the vulnerability of freshly isolated mice hepatocytes towards pro-oxidant conditions, as ascertained by the increase in collagen deposition, lower hepatocyte yield and decreased glutathione levels. However, MDMA toxicity to the isolated hepatocytes was independent of ethanol pre-treatment, while significantly dependent on incubation temperature.  相似文献   
75.
Morton  JD; Harrison  LB; Peschel  RE 《Radiology》1986,159(1):249-252
Of 179 patients with stage B or C adenocarcinoma of the prostate, 106 underwent iodine-125 seed-implant therapy (I-125 SI) and 73 received external-beam radiation therapy (EB). A retrospective analysis determined disease-free survival rate, local tumor control, and complication rate for each treatment group. The 5-year disease-free survival rates for SI-treated patients were 75% for stage B and 30% for stage C groups. Corresponding rates for EB-treated patients were 75% and 40%, respectively. The rate of local tumor control for stage B patients was 85% for SI-treated and 88% for EB-treated patients. The corresponding rates for stage C tumors were 75% for SI-treated and 92% for EB-treated patients. The rate of long-term complications in each group was approximately 10%. For stage B cancer of the prostate, I-125 SI treatment is an acceptable alternative to EB therapy; our data are inconclusive regarding stage C treatment, but EB therapy is preferred.  相似文献   
76.
Previously we showed that IL2 expanded tumor-infiltrating lymphocytes (TILs) from renal cell carcinoma mediated non-major histocompatibility complex-restricted cytotoxicity. Phenotypic analysis showed that cultured TILs were composed mostly of T-lymphocytes with varying numbers of CD4+, CD8+, and CD56+ (Leu19+) populations. Here we compared the cytolytic activity of the two predominant TIL subsets, CD3+CD4+ and CD3+CD8+, to that of the CD56+ populations. Using magnetic beads coated with antibodies to either CD4 or CD8, CD3+CD4+, and CD3+CD8+ TILs were isolated in a highly enriched form (greater than 92%) and could be expanded for over 40 days in vitro with 1000 units/ml IL2. In a 4-h 51Cr release assay the CD4+ and CD8+ TILs showed minimal lytic activity, whereas unseparated cells exhibited significant levels of non-major histocompatibility complex-restricted cytotoxicity. The lytic activity seen in the 4-h assay with unseparated TILs appeared to be related to the presence of CD56+ populations. With one exception none of the purified CD4+ or CD8+ TILs expressed any significant levels of CD56, while the unseparated TILs contained varying numbers of CD3+CD56+ and CD3-CD56+ populations. Cell-sorting experiments verified that the CD56+ populations were responsible for most of the lytic activity in 4 h even though CD3+CD56- cells represented the predominant cell type. Although CD3+CD56- TILs were minimally lytic in 4 h, we show here that both CD3+CD4+ and CD3+CD8+ subsets displayed substantial cytotoxicity in long-term assays. In the 18-h 51Cr release assay 5 of 6 CD4+ and 2 of 3 CD8+ TILs were lytic for the autologous tumor. In two cases, restimulation with the autologous tumor induced augmented cytolytic activity of TIL subsets and in one case induced lytic activity in 4 h. The cytotoxic activity of TIL subsets was further examined using a 72-h assay in which TILs were cocultured with a confluent layer of tumor cells. The degree of cytotoxicity was quantitated by measuring the amount of crystal violet dye that was incorporated by tumor cells which remained after the incubation period. CD4+ and CD8+ TILs typically caused greater than a 50% reduction of tumor cells in 3 days and the level of reduction was increased when IL2 was added to the cultures. All the CD4+ and CD8+ subset preparations were cytotoxic in the 3-day assay even though some were not lytic for certain targets in the 18-h 51Cr release assay.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
77.
78.
The 13th edition of the standards of the American Association of Blood Banks specified storage at 1 to 6 degrees C for cryoprecipitated anti-hemophilic factor (Cryo) administered up to 6 hours after thawing if the Cryo is used for factor VIII (FVIII) content (Standard J4.210). Previous editions specified room-temperature (RT) storage for up to 6 hours. Currently, the temperature specification has been deleted. There are few data addressing the optimal storage temperature and maximum storage time for FVIII and fibrinogen in thawed Cryo. Thirty bags of Cryo were assayed for FVIII and fibrinogen. Each bag was divided into two aliquots; one was stored at RT and the other at 1 to 6 degrees C. Assays were performed immediately after thawing (Base) and 6 and 24 hours after thawing, respectively. All samples were filtered through 200-mu blood component infusion sets before assay. Three hundred analyses were performed, 150 each for FVIII and fibrinogen by conventional clotting technique. Data were analyzed by using a paired t test. Cryo stored at 1 to 6 degrees C for 6 and 24 hours showed an FVIII loss of 35 percent (p less than 0.0001) and 63 percent (p less than 0.0001), respectively. Cryo stored at RT for 6 and 24 hours had an FVIII loss of 8 percent (p greater than 0.05) and 20 percent (p less than 0.0001). Cryo stored at 1 to 6 degrees C for 6 and 24 hours had a fibrinogen loss of 20 percent (p less than 0.0001) and 43 percent (p less than 0.0001). Cryo stored at RT for 6 hours had no fibrinogen loss and a 2 percent loss at 24 hours (p greater than 0.05). These preliminary data show a significant loss of FVIII and fibrinogen activity in Cryo stored at 1 to 6 degrees C and filtered before assay. The FVIII and fibrinogen activity at RT is clearly maintained up to 6 hours after thawing.  相似文献   
79.
A near-fatal reaction during granulocyte transfusion of a neonate   总被引:1,自引:0,他引:1  
Although reactions to granulocyte transfusions in neonates are rarely reported, we observed a near-fatal pulmonary reaction, presumably due to white cell antibodies, in a neonate with Rh hemolytic disease. The hemolytic disease was being treated with exchange transfusions, and at 2 days after the infant's birth, bacterial sepsis was suspected and granulocyte transfusions were begun. The first granulocyte transfusion (Day 3) was uneventful. Five minutes after the beginning of the second granulocyte transfusion (Day 4), severe respiratory distress, hypotension, bradycardia, cyanosis, and acidosis suddenly occurred. The infant's serum obtained after the reaction contained granulocytotoxic and B-lymphocytotoxic antibodies that reacted with leukocytes from the second granulocyte donor. Antibodies could not be detected either in the initial infant serum or in maternal serum. However, an antileukocyte antibody was present in the serum of a parous woman donor. We used plasma from this woman to prepare reconstituted whole blood for the exchange transfusion that we performed immediately preceding the second granulocyte transfusion. Despite the sequence of events, an irrefutable cause-and-effect mechanism could not be established because the properties of the donor and neonatal antibodies were similar, but not identical. However, this catastrophic event emphasizes both the potential for adverse effects of granulocyte transfusions in neonates and the need for caution when transfusing blood from parous women.  相似文献   
80.
This report describes a cross-sectional survey on the prevalence of hepatitis C antibodies (anti-HCV) in Tamboara, a small community in the northwest area from Paraná State, south of Brazil with a high rate of accumulated detection for HCV. Eight hundred and sixteen residents (17.87% from all the population), independently of the age and time living in Tamboara were included in this study by an epidemiologic questionnaire and by testing for anti-HCV. The rapid immuno-chromatographic test was applied for detection of HCV antibodies. The anti-HCV prevalence by rapid test was 4.28%. The median age for positive and negative test was 60.49 ± 14.14 and 41.67 ± 20.25, respectively (p < 0.001). By multivariate analysis, only familial history of hepatitis (p = 0.001; OR = 6.41; CI 95% = 2.08-19.78) and age (p = 0.007; OR 1.06;95% CI = 1.02-1.10) showed statistical significance for positive anti-HCV. The rapid test sensitivity and specificity were 100% and 92.7% respectively, with an accuracy of 95.8% (95% CI = 91-100). These findings demonstrated a high prevalence of anti-HCV in Tamboara. The familial history of hepatitis was a significant risk factor to the infection and HCV rapid test showed to be accurate and feasible for epidemiological survey.  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