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   8787篇
  免费   376篇
  国内免费   20篇
耳鼻咽喉   109篇
儿科学   125篇
妇产科学   120篇
基础医学   1167篇
口腔科学   174篇
临床医学   568篇
内科学   2467篇
皮肤病学   217篇
神经病学   579篇
特种医学   354篇
外科学   1088篇
综合类   48篇
预防医学   220篇
眼科学   150篇
药学   832篇
中国医学   12篇
肿瘤学   953篇
  2023年   37篇
  2022年   71篇
  2021年   137篇
  2020年   78篇
  2019年   107篇
  2018年   125篇
  2017年   96篇
  2016年   108篇
  2015年   157篇
  2014年   170篇
  2013年   232篇
  2012年   388篇
  2011年   474篇
  2010年   239篇
  2009年   176篇
  2008年   424篇
  2007年   455篇
  2006年   412篇
  2005年   405篇
  2004年   445篇
  2003年   426篇
  2002年   431篇
  2001年   346篇
  2000年   395篇
  1999年   291篇
  1998年   99篇
  1997年   72篇
  1996年   73篇
  1995年   73篇
  1994年   51篇
  1993年   58篇
  1992年   184篇
  1991年   166篇
  1990年   156篇
  1989年   178篇
  1988年   144篇
  1987年   138篇
  1986年   141篇
  1985年   148篇
  1984年   98篇
  1983年   102篇
  1981年   43篇
  1980年   39篇
  1979年   71篇
  1978年   48篇
  1977年   37篇
  1975年   42篇
  1970年   42篇
  1968年   39篇
  1967年   43篇
排序方式: 共有9183条查询结果,搜索用时 15 毫秒
41.
A new commercial rapid 10-min one-step immunochromatography (IC) test, SAS RSV test, was compared to another IC test, Directigen EZ RSV, employing RT-PCR as the "gold standard" for detecting respiratory syncytial virus. Of 102 clinical samples, 79 were positive by RT-PCR, 66 (82.5%) were positive with the SAS RSV test, and 55 (69.6%) were positive with Directigen EZ RSV. The specificity of the new test was 91.3% (21 of 23), similar to that of Directigen EZ RSV (100% [23 of 23]). This test performs well enough to be used for patient care.  相似文献   
42.
43.
Five autopsy cases of thrombotic microangiopathy, including 3 cases associated with acute promyelocytic leukaemia, were examined macroscopically, light-and electronmicroscopically.
The so-called hyaline thrombi In thrombotic microangiopathy were composed of fibrin and its degenerative products. Thrombocytes and other blood cells were not seen in the thrombi.
At the site of the formation of a thrombus, there was no conspicuous change in the walls of the capillaries and arterioles. It was considered, therefore, that the intravascular deposition of fibrin was the primary event in the development of thrombotic microangiopathy.
In regard to the distribution and morphologic findings, there was no basic difference between the microthrombi in cases associated with acute promyelocytic leukaemia and those without it.
The bone marrow and some other organs in cases of thrombotic microangiopathy associated with acute promyelocytic leukaemia macroscopically revealed a green colour. Many thrombi composed of leukaemic cells and fibrin were found in the pulmonary arteries of these cases. Furthermore, prominent erythrophagocytosis in the bone marrow and lymph nodes was a common finding in these cases.  相似文献   
44.
A protein, isolated and purified from the unheated culture filtrate of Mycobacterium bovis BCG (substrain Tokyo 172) and designated MPB70, elicited a delayed skin reaction in guinea pigs sensitized with viable cells of BCG but not in those sensitized with heat-killed cells. The skin reaction reached the maximum 4 to 8 weeks after the inoculation of the BCG and then decreased gradually, resulting in conversion to negative after 20 weeks, whereas the skin reaction to purified protein derivative (PPD) continued to be positive. Guinea pigs immunized with viable cells of various substrains of BCG were skin tested with MPB70 and PPD. Guinea pigs immunized with the BCG substrain Tokyo 172 and the substrain Moreau (Brazil) showed strong delayed skin reactions to both MPB70 and PPD. On the other hand, guinea pigs immunized with the Pasteur substrain 1173P2, the Glaxo substrain 1077, the Copenhagen substrain 1331, the Tice substrain, or the Beijing substrain 64-42 showed negative skin reactions to MPB70, whereas they were strongly positive to PPD. In a two-dimensional acrylamide gel electrophoretic analysis of proteins from the culture filtrates of the BCG substrains, the culture filtrates of the Tokyo and Moreau substrains showed the spot of MPB70 on the gel slabs, whereas those of the other BCG substrains did not.  相似文献   
45.
Summary Nineteen hybridomas producing monoclonal antibodies (MAbs) against the structural proteins of strain 58–17, a subgroup B field strain of respiratory syncytial virus (RSV) isolated in Japan, were obtained by fusion of X 63 myeloma cells with spleen cells from BALB/c mice immunized with the virus-infected HEp-2 cells. Seven clones were found to produce antibodies against the fusion protein (F), five against the large glycoprotein (G), five against the nucleoprotein (NP) and two against the 22k protein by radioimmunoprecipitation assay. By competitive binding assay with the MAbs, at least seven, two, three and one epitopes were defined on the F, G, NP and 22k protein components of subgroup B strain, respectively. Of these epitopes, three, two and one epitopes on the F, G and NP components were different from subgroup A strain, respectively. Fifty-three other field strains of subgroup B isolated in Sapporo, Japan, during nine epidemic years from 1980 to 1989, were examined for reactivity with the MAbs by ELISA. Different reactivity to one anti-NP antibody suggested that the 53 strains can be divided into three groups (B-a: 26 strains, B-b: 26 strains, and one other strain). The dominant strain prevailing during the 1984 to 1988 epidemic years had changed from B-a to B-b. All of the 53 subgroup B strains reacted similarly with the other 18 MAbs.  相似文献   
46.
The Thy-1 antigens or rat brain and thymus have been isolated and chemically characterized, but those of mice have not been identified. Moreover, it is uncertain whether the antigens are glycolipids or glycoproteins. This study with highly purified preparations of gangliosides GM1, 1GD1a, GD1b and GT1b from bovine brain and several ganglioside fractions from mouse brain showed that Thy-1 activity does not reside in gangliosides, but rather in the chloroform-methanol-insoluble residue of brain remaining after extraction of gangliosides. The antigen could be solubilized from this residue with a non-ionic detergent. The antigenic activity of the solubilized preparation was heat-labile but resistant to periodate. The chemical properties of the Thy-1 antigen of mouse brain are discussed.  相似文献   
47.
A new algorithmic-based digital filter processing system for real-time continuous blood pressure (BP) measurement and analysis in freely-moving conscious rats has been developed. Real-time recognition of BP waveforms, real-time noise rejection and determination of representative waveform indexes (WIs) at indicated time points using digital filters and Smirnov's rejection test were realized with this system. Digital filters were applied for two different purposes: waveform segmentation and smoothing the calculations of representative WIs. Smirnov's rejection test was used for real-time noise rejection and yielded an accurate rejection rate of 99.99%. The result was that the digital filter processing and Smirnov's rejection test realized accurate real-time BP measurement and analysis in freely-moving conscious rats using a personal computer.  相似文献   
48.
49.
An improved system is described to recover non-transmissible Sendai virus that lack the envelope fusion (F) gene from cloned cDNA. The system (1) used plasmids that expressed the F and the HN viral envelope proteins, as well as the plasmids that expressed the viral NP, P, and L proteins as helper plasmids for recovery, and (2) overlaid packaging cells that expressed the F protein. With this improved system, we have succeeded in recovery of F-defective Sendai virus expressing two foreign proteins, and expression vectors that do not contain the EGFP reporter gene. This system may provide the basis for constructing recombinant F-defective Sendai virus for preventing and treating human diseases in the form of vaccines and vectors for gene therapy.  相似文献   
50.
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