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   1643201篇
  免费   111277篇
  国内免费   2568篇
耳鼻咽喉   22720篇
儿科学   53324篇
妇产科学   43188篇
基础医学   243026篇
口腔科学   46109篇
临床医学   147974篇
内科学   309113篇
皮肤病学   37447篇
神经病学   121656篇
特种医学   63295篇
外国民族医学   276篇
外科学   246591篇
综合类   33861篇
现状与发展   3篇
一般理论   404篇
预防医学   118006篇
眼科学   38348篇
药学   129358篇
  10篇
中国医学   4712篇
肿瘤学   97625篇
  2019年   12242篇
  2018年   17628篇
  2017年   13784篇
  2016年   15504篇
  2015年   17284篇
  2014年   23600篇
  2013年   34939篇
  2012年   47298篇
  2011年   49939篇
  2010年   29367篇
  2009年   27641篇
  2008年   46229篇
  2007年   49603篇
  2006年   50485篇
  2005年   47637篇
  2004年   45993篇
  2003年   44066篇
  2002年   42649篇
  2001年   86443篇
  2000年   88335篇
  1999年   73435篇
  1998年   18770篇
  1997年   16322篇
  1996年   16518篇
  1995年   15629篇
  1994年   14186篇
  1993年   13362篇
  1992年   55340篇
  1991年   54069篇
  1990年   53010篇
  1989年   51427篇
  1988年   46529篇
  1987年   45282篇
  1986年   42877篇
  1985年   40229篇
  1984年   29385篇
  1983年   24859篇
  1982年   13768篇
  1979年   26577篇
  1978年   18248篇
  1977年   15959篇
  1976年   14410篇
  1975年   16289篇
  1974年   18988篇
  1973年   18297篇
  1972年   17396篇
  1971年   16283篇
  1970年   15241篇
  1969年   14453篇
  1968年   12978篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
131.
BACKGROUND: We prospectively evaluated the usefulness of IgA tissue transglutaminase antibodies (IgA tTG) in the initial diagnosis of celiac disease (CD) and compared its diagnostic potential with that of IgA anti-endomysial antibodies (IgA EMA) and anti-IgA and IgG gliadin antibodies (AGA and AGG, respectively). METHODS: Sera of 23 untreated children fulfilling the revised ESPGHAN criteria for diagnosis of CD (Group I; mean age 10.8 y); 19 disease controls (Group II; mean age 8.5 y) presenting with chronic diarrhea, short stature or both; and 22 healthy children (Group III; mean age 8.8 y) were studied. These were tested in a blinded manner for AGA, AGG, IgA tTG (guinea pig as antigen) and IgA EMA. RESULTS: In Group I, IgA EMA was positive in 19, IgA tTG in 17, AGA in 14 and AGG in 17 patients. In Group II, these tests were positive in 1, 0, 2 and 14 patients, respectively and in Group III, in 0, 0, 0 and 1 child, respectively. Analyzing data from Group I and II, IgA EMA, IgA tTG, AGA and AGG had sensitivity rates of 83%, 74%, 61% and 74%, respectively; the specificity rates were 95%, 100%, 89% and 26%; positive predictive values were 95%, 100%, 88% and 55% and negative predictive values were 82%, 74%, 65% and 45%, respectively. CONCLUSION: IgA tTG is useful for the diagnosis of CD, with sensitivity and specificity rates comparable to those of EMA and this test is well suited for use in tropical countries like India.  相似文献   
132.
Interferon-alpha (IFN-alpha) has proved effective in the treatment of hemangiomas, hemangioblastomas, and Kaposi's sarcoma. To investigate the ability of IFNs to inhibit angiosarcoma, we used two transformed murine endothelial cell lines that form angiosarcomas in vivo. SVR and MS1-VEGF cell lines express oncogenic H-ras or vascular endothelial growth factor (VEGF), respectively. IFN-alpha1,8, which is active against murine and human cells, inhibited SVR and MS1-VEGF proliferation in vitro by 40% at 10(3) U/mL (p = 0.028). In vivo, IFN-alpha1,8 inhibited SVR tumor volume by 71% (p = 0.047) and MS1-VEGF volume by 79% (p = 0.003). Tumor-induced angiogenesis was decreased in SVR tumors by 52% (p = 0.005) and in MS1-VEGF tumors by 58% (p = 0.001). Sera from IFN-alpha1,8-treated mice bearing either SVR or MS1-VEGF tumors demonstrated a 5-fold increase in IP-10/CXCL10 (p = 0.001), an IFN-induced antiangiogenic protein. Both recombinant IP-10 and IFN-alpha1,8 inhibited human umbilical vein endothelial cell (HUVEC) vessel formation in the fibrin gel assay, a three-dimensional culture model of angiogenesis, by 56% at 25 ng/mL and 50% at 1.2 ng/mL, respectively (p < 0.001). An IP-10 blocking antibody restored vessel formation to 80% of untreated controls (p = 0.001). Given the magnitude of the in vivo response, these data suggested that the antitumor effects of IFN-alpha1,8 were likely mediated through angiogenesis inhibition rather than solely by direct inhibition of tumor cell proliferation.  相似文献   
133.
A rapid procedure for determining angiotensin II in the blood by inverse voltammetry using a TA-2 device (Tekhnoanalit Company, Tomsk) with a graphite electrode has been developed. The results of analyses using the proposed technique agree with the clinical data. The rapid analytical procedure favors optimization of cardiotropic drug therapy. __________ Translated from Khimiko-Farmatsevticheskii Zhurnal, Vol. 40, No. 12, pp. 54–56, December, 2006.  相似文献   
134.
135.
136.
Successful efforts in improving breastfeeding initiation rates at an urban teaching hospital prompted the hospital to create a lactation consultant (LC) position in the outpatient setting to focus on breastfeeding duration. This article reviews the complexity of the clinic setting, with the challenges and benefits of the consultant's first year in one of the hospital's outpatient clinics. Preliminary data collected by the consultant suggest that patients counseled by the LC in the outpatient clinic setting have longer breastfeeding duration rates.  相似文献   
137.
The incidence of uterine cervical cancer has increased slightly in Western countries, with an increase in relatively young women. Overexpression of matrix metalloproteinases (MMPs)-2 and -9 has turned out as a prognostic factor in many cancers. We compared the expression of the proteins MMP-2 and MMP-9 in cervical primary tumors with clinical outcome and risk factors of cervical cancer. One hundred sixty-one patients with cervical cancer treated in Ume? University Hospital or Sahlgrenska University Hospital, Sweden, between 1991 and 1995 were included in the study. Paraffin-embedded tissue samples obtained prior to treatment were examined immunohistochemically by specific antibodies for MMP-2 and MMP-9. Forty-two percent of the tumors were intensively positive for MMP-2 and 31% for MMP-9. Nineteen percent of the samples were intensively positive for both proteinases and 47% negative or weak for both. Overexpression of MMP-2 seemed to predict unfavorable survival under Kaplan-Meier analysis and in the multivariate analysis. Early sexual activity and low parity seemed to correlate to overexpression of MMP-2. MMP-9 was not associated with survival or sexual behavior. Intensive MMP-9 was noted in grade 1 tumors. We conclude that MMP-2 and MMP-9 have different roles in uterine cervical cancer. MMP-2 could be associated with aggressive behavior, but MMP-9 expression diminishes in high-grade tumors.  相似文献   
138.
139.
140.
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