全文获取类型
收费全文 | 4643篇 |
免费 | 247篇 |
国内免费 | 182篇 |
专业分类
耳鼻咽喉 | 358篇 |
儿科学 | 29篇 |
妇产科学 | 26篇 |
基础医学 | 770篇 |
口腔科学 | 78篇 |
临床医学 | 122篇 |
内科学 | 388篇 |
皮肤病学 | 248篇 |
神经病学 | 371篇 |
特种医学 | 66篇 |
外科学 | 615篇 |
综合类 | 852篇 |
预防医学 | 144篇 |
眼科学 | 159篇 |
药学 | 671篇 |
中国医学 | 143篇 |
肿瘤学 | 32篇 |
出版年
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 46篇 |
2020年 | 54篇 |
2019年 | 54篇 |
2018年 | 56篇 |
2017年 | 74篇 |
2016年 | 87篇 |
2015年 | 97篇 |
2014年 | 142篇 |
2013年 | 188篇 |
2012年 | 174篇 |
2011年 | 172篇 |
2010年 | 149篇 |
2009年 | 153篇 |
2008年 | 184篇 |
2007年 | 195篇 |
2006年 | 234篇 |
2005年 | 189篇 |
2004年 | 201篇 |
2003年 | 195篇 |
2002年 | 183篇 |
2001年 | 164篇 |
2000年 | 147篇 |
1999年 | 125篇 |
1998年 | 111篇 |
1997年 | 127篇 |
1996年 | 118篇 |
1995年 | 99篇 |
1994年 | 99篇 |
1993年 | 83篇 |
1992年 | 101篇 |
1991年 | 94篇 |
1990年 | 92篇 |
1989年 | 81篇 |
1988年 | 74篇 |
1987年 | 73篇 |
1986年 | 58篇 |
1985年 | 89篇 |
1984年 | 85篇 |
1983年 | 73篇 |
1982年 | 53篇 |
1981年 | 53篇 |
1980年 | 37篇 |
1979年 | 35篇 |
1978年 | 38篇 |
1977年 | 26篇 |
1976年 | 22篇 |
1974年 | 12篇 |
1973年 | 15篇 |
排序方式: 共有5072条查询结果,搜索用时 15 毫秒
81.
IHA和Slide诊断旋毛虫病的研究 总被引:1,自引:0,他引:1
目的 :检测感染旋毛虫病豚鼠血清 ,寻求新的诊断旋毛虫病的方法。方法 :采用间接红细胞凝集试验(IHA)和玻片法环蚴沉淀试验 (Slide)。结果 :阳性率分别为 10 0 %和 97.1%。用此两种血清学方法检测正常豚鼠、血吸虫病兔、肺吸虫病大白鼠、蛔虫病人和鞭虫病人血清 ,除 1例肺吸虫病大白鼠血清IHA出现阳性反应外 ,其它血清两种方法均为阴性反应。结论 :提示两种免疫血清学方法对旋毛虫病特异性抗体的检测均具有较好的敏感性和特异性 相似文献
82.
目的:建立一种炎性胸膜腔积液(简称胸液)的动物模型。方法:选择40只豚鼠分为8组,第1-7组为试验组,第8组为对照组,试验组每只左胸膜腔内注入1%角叉菜胶(carrageenan)0.8-1.0ml,分批处死观察。结果:胸液于1天内已经出现,2-3天积液量最多,胸液中中性粒细胞计数及病理切片中胸膜、肺的炎性改变亦达高峰,以后胸液逐渐吸收,第7天开始出现胸膜纤维化与粘连,第10天时明显,14天呈现胸膜包裹。结论:角叉菜胶是一比较理想的胸膜腔致炎剂;该动物模型的建立,为胸液的进一步研究提供了有用的工具。 相似文献
83.
David K. C. Cooper Hidetaka Hara Hayato Iwase Takayuki Yamamoto Zheng‐Yu Wang Abhijit Jagdale Mohamed H. Bikhet Huy Q. Nguyen Jeremy B. Foote Wayne D. Paris David Ayares Vineeta Kumar Douglas J. Anderson Jayme E. Locke Devin E. Eckhoff 《Clinical transplantation》2021,35(1):e14139
Pig organ xenotransplantation offers a solution to the shortage of deceased human organs for transplantation. The pathobiological response to a pig xenograft is complex, involving antibody, complement, coagulation, inflammatory, and cellular responses. To overcome these barriers, genetic manipulation of the organ‐source pigs has largely been directed to two major aims—(a) deletion of expression of the known carbohydrate xenoantigens against which humans have natural (preformed) antibodies, and (b) transgenic expression of human protective proteins, for example, complement‐ and coagulation‐regulatory proteins. Conventional (FDA‐approved) immunosuppressive therapy is unsuccessful in preventing an adaptive immune response to pig cells, but blockade of the CD40:CD154 costimulation pathway is successful. Survival of genetically engineered pig kidneys in immunosuppressed nonhuman primates can now be measured in months. Non‐immunological aspects, for example, pig renal function, a hypovolemia syndrome, and rapid growth of the pig kidney after transplantation, are briefly discussed. We suggest that patients on the wait‐list for a deceased human kidney graft who are unlikely to receive one due to long waiting times are those for whom kidney xenotransplantation might first be considered. The potential risk of infection, public attitudes to xenotransplantation, and ethical, regulatory, and financial aspects are briefly addressed. 相似文献
84.
目的 探讨杏贝止咳颗粒对豚鼠感染后咳嗽(post-infectious cough,PIC)的治疗作用。方法 除对照组外,将3~4周龄SPF级雄性Hartley豚鼠采用鼻滴脂多糖、烟熏、辣椒素雾化激发来构建PIC豚鼠模型。造模成功后分为模型组及杏贝止咳颗粒低、中、高剂量(0.93、1.86、3.72 g/kg)组、阿斯美(21.62 mg/kg)组和苏黄止咳胶囊(313.88 mg/kg)组,末次给药后24 h,通过辣椒素雾化诱咳测定咳嗽次数及潜伏期,采用ELISA法检测血清、肺泡灌洗液和肺组织中P物质(substance P,SP)、降钙素相关基因肽(calcitonin gene related peptide,CGRP)、神经肽A(neurokinin A,NKA)、神经肽B(neurokinin B,NKB)、神经生长因子(nerve growth factor,NGF)、前列腺素E2(prostaglandin E2,PGE2)和缓激肽(bradykinin,BK)含量,血液分析仪测定肺泡灌洗液中白细胞分类,并用苏木素-伊红(HE)染色法观察肺组织病理变化。结果 与对照组比较... 相似文献
85.
哮喘豚鼠初级传入神经元ERK的表达及NGF的调节作用 总被引:7,自引:2,他引:7
目的 探讨细胞外信号调节蛋白激酶 (ERK)在哮喘豚鼠初级传入神经元 (C7 T5脊神经节 )的表达及神经生长因子 (NGF)对ERK的调节作用。方法 利用免疫组织化学结合显微图像分析 ,研究哮喘豚鼠C7 T5脊神经节活化的ERK免疫反应变化。结果 与对照组相比 ,哮喘组豚鼠活化ERK免疫反应在C7 T5脊神经节神经元核内明显上调 (P <0 .0 1) ,其阳性细胞比率明显高于对照组。Anti NGF组豚鼠活化ERK免疫反应在C7 T5脊神经节神经元的核中明显低于哮喘组 (P <0 .0 1)。结论 C7 T5脊神经节神经元活化的ERK可能参与哮喘的发病过程 ,NGF可上调哮喘豚鼠C7 T5脊神经节神经元活化的ERK表达 相似文献
86.
During preparation of cells for experimentation a considerable amount of bound substance is lost. Our aim was to develop a protocol which retained lectin binding to an extent similar to living cells. This procedure would use fixation procedures suited for fluorescent lectin conjugates and gold-conjugates to be visualized by light- and electron microscopy, respectively. We tested glutaraldehyde and paraformaldehyde in different concentrations before and after lectin binding, different buffers and divalent cations, as additives, to determine the effects on preservation of lectin binding. Lectin binding was visualized and semiquantitatively evaluated by image analysis in the light microscope after silver enhancement of lectin-gold conjugates and by using tetramethyl rhodaminyl isothiocyanate (TRITC)-conjugated lectins. Preservation of lectin binding was best visualized with fluorescent lectin conjugates, whereas during silver enhancement procedures of gold-conjugated lectins, a considerable amount of bound lectins was lost. In general, lectin binding to living cells followed by fixation is superior to fixation before lectin binding. Unfavourable combinations of fixatives and buffers can cause a loss of more than 90% bound lectin. In our experiments with freshly isolated guinea pig cardiomyocytes, lectin binding was best when we used Na-cacodylate buffer with glutaraldehyde fixation (0.1%) after binding of lectins to the living cells. 相似文献
87.
88.
89.
The ontogeny of lymphocytes expressing J chain in the cytoplasm (J+) was studied in pig foetuses by the immunofluorescent technique. Peripheral blood lymphocytes were the first J+ cells in prenatal life. The spleen and lymph nodes contained J+ cells in the last days of gestation. J+ cells were found in the lamina propria of the gut and some glands of conventional but not of germ-free piglets. J chain was not detected on or in cell membranes at any developmental stage. 相似文献
90.
Mitsuo Shimada Katsuhiko Yanaga Keiji Kishikawa Saburo Kakizoe Hidetoshi Itasaka Tetsuo Ikeda Taketoshi Suehiro Keizo Sugimachi 《Transplant international》1993,6(1):4-7
Rapid and reliable assessment of hepatic graft viability is important for successful orthotopic liver transplantation (OLTx). OLTx was performed in 11 pairs of pigs via a venovenous bypass. Six of these grafts were transplanted immediately (group A), while the other five were preserved in University of Wisconsin (UW) solution for 24 h and then transplanted (group B). All grafts were flushed with 300 ml of chilled (4°C) Ringer's lactate solution before reperfusion of the graft, when 20 ml of effluent from the graft was collected and the concentrations of ammonia, lactic acid, GOT, and LDH were measured. Four of the six pigs in group A survived longer than 3 days, while the other two pigs died of causes other than graft dysfunction. All five pigs in group B died either of hemoperitoneum or hemodynamic instability due to liver failure. The histology of postperfusion biopsies in group A showed minimal pathological changes, while the grafts in group B revealed moderate to severe ischemic injuries. Ammonia and lactic acid in the effluent of group B were significantly higher than those of group A (1511±216 vs 417±333 g/dl and 114.1±12.2 vs 91.4±12.2 mg/dl, respectively; P<0.05 in both cases). Before reperfusion, the rate of total adenine nucleotides in all of the substances in the graft, which were measured using high performance liquid chromatography (HPLC), inversely correlated with the ammonia levels in the effluent. We conclude that an analysis of the effluent, (i.e. the levels of ammonia and lactic acid), flushed from a hepatic graft before reperfusion could serve as a predictor of hepatic graft viability. 相似文献