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   2839102篇
  免费   212634篇
  国内免费   6299篇
耳鼻咽喉   37601篇
儿科学   93335篇
妇产科学   78296篇
基础医学   403440篇
口腔科学   81357篇
临床医学   253999篇
内科学   558955篇
皮肤病学   65488篇
神经病学   226695篇
特种医学   105790篇
外国民族医学   697篇
外科学   423257篇
综合类   64488篇
现状与发展   7篇
一般理论   967篇
预防医学   223854篇
眼科学   67180篇
药学   206081篇
  7篇
中国医学   6987篇
肿瘤学   159554篇
  2021年   22379篇
  2019年   23763篇
  2018年   34677篇
  2017年   25886篇
  2016年   28587篇
  2015年   32181篇
  2014年   44464篇
  2013年   66122篇
  2012年   92112篇
  2011年   97681篇
  2010年   56857篇
  2009年   52792篇
  2008年   89452篇
  2007年   95049篇
  2006年   95631篇
  2005年   91989篇
  2004年   88314篇
  2003年   84067篇
  2002年   81011篇
  2001年   140995篇
  2000年   144833篇
  1999年   119741篇
  1998年   32761篇
  1997年   28789篇
  1996年   28862篇
  1995年   27599篇
  1994年   25184篇
  1993年   23417篇
  1992年   91074篇
  1991年   87318篇
  1990年   84125篇
  1989年   80680篇
  1988年   73914篇
  1987年   72187篇
  1986年   67759篇
  1985年   64522篇
  1984年   48146篇
  1983年   40744篇
  1982年   23733篇
  1979年   42773篇
  1978年   29742篇
  1977年   25101篇
  1976年   23621篇
  1975年   24674篇
  1974年   29914篇
  1973年   28922篇
  1972年   26972篇
  1971年   24789篇
  1970年   23369篇
  1969年   21906篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Thoraxtrauma     
Chest injuries can be sustained in isolation or in association with multiple injuries. Life-threatening complications may ensue because organs that are vital to survival of the organism are situated within the thoracic cavity. These complications include airway obstruction, tension pneumothorax, wide open pneumothorax, flail chest, cardiac tamponade and massive hemothorax. The mortality of patients hospitalized with chest injury can be as high as 10%. Clinical examination and awareness of the possibility of other injuries (high level of suspicion) are essential, and standard chest X-ray, ultrasound and thoracic computed tomography may also be needed for the diagnosis. The first part of this serial paper on the management of chest injuries focuses on anatomical aspects, pathophysiology and symptoms, but mainly on the indications for the standard diagnostic procedures and further high-tech examinations.  相似文献   
993.
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   
994.
This study examined the ability of PCR to amplify Leishmania DNA, stored on Giemsa-stained slides, from American cutaneous leishmaniasis (ACL) patients. In total, 475 slides stored for up to 36 years were obtained from an outpatient clinic in a Brazilian ACL-endemic region, and Leishmania DNA was amplified from 395 (83.2%) of the DNA samples using primers specific for the minicircle kinetoplast DNA. Restriction fragment length polymorphism analysis of these amplicons demonstrated that Leishmania (Viannia) braziliensis was the only species present in these samples. The results demonstrated that archived Giemsa-stained slides can provide a Leishmania DNA source for performing clinical and epidemiological studies of leishmaniasis.  相似文献   
995.
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   
996.
997.
In the last 20 years, cases of human cryptococcosis, have increased in immunocompromised patients. In several instances, the cases have been associated with the exposure of the patients to bird droppings. In order to investigate birds of prey as potential carriers and spreaders of Cryptococcus neoformans and other yeasts of importance in human infections, 182 swab samples were collected from the cloacae of several species of birds of prey (Group I) and 32 faecal samples from aviaries in which the birds were housed (Group II). Samples were also taken from digestive tract of 60 dead birds (Group III). A total of 454 samples were cultured from which 215 colonies of yeastlike fungi were recovered and identified. Cryptococcusneoformans var. grubii was isolated from three cloacae samples (4.8%) collected from Falco tinnunculus and from one sample (3.1%) obtained from Buteo buteo, as well as from samples collected at the aviaries in which these birds were kept. Overall, 18 samples (9.9%) from Group I, 13 (40.6%) from Group II, 12 crops (20%), three proventriculi (5%) and 12 cloacae (20%) from Group III yielded positive cultures for yeasts. The results indicate that birds of prey and in particular, F. tinnunculus and B. buteo, may act as carriers and spreaders of C. neoformans and other zoonotic yeasts.  相似文献   
998.
999.
1000.
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