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   20921篇
  免费   1894篇
  国内免费   40篇
耳鼻咽喉   234篇
儿科学   655篇
妇产科学   392篇
基础医学   2956篇
口腔科学   318篇
临床医学   2238篇
内科学   4162篇
皮肤病学   305篇
神经病学   1893篇
特种医学   632篇
外国民族医学   3篇
外科学   2660篇
综合类   476篇
一般理论   14篇
预防医学   2177篇
眼科学   724篇
药学   1574篇
中国医学   22篇
肿瘤学   1420篇
  2021年   317篇
  2020年   238篇
  2019年   361篇
  2018年   373篇
  2017年   282篇
  2016年   335篇
  2015年   396篇
  2014年   555篇
  2013年   814篇
  2012年   1217篇
  2011年   1301篇
  2010年   628篇
  2009年   663篇
  2008年   1084篇
  2007年   1233篇
  2006年   1172篇
  2005年   1192篇
  2004年   1156篇
  2003年   992篇
  2002年   990篇
  2001年   448篇
  2000年   475篇
  1999年   483篇
  1998年   299篇
  1997年   218篇
  1996年   227篇
  1995年   199篇
  1994年   172篇
  1993年   151篇
  1992年   309篇
  1991年   309篇
  1990年   296篇
  1989年   291篇
  1988年   259篇
  1987年   245篇
  1986年   274篇
  1985年   230篇
  1984年   203篇
  1983年   155篇
  1982年   155篇
  1981年   122篇
  1980年   121篇
  1979年   193篇
  1978年   143篇
  1977年   108篇
  1976年   100篇
  1975年   99篇
  1974年   113篇
  1973年   131篇
  1972年   94篇
排序方式: 共有10000条查询结果,搜索用时 38 毫秒
41.
Background - A case of primary thyroid T cell lymphoma leading to lethal tracheal perforation during chemotherapy is described.  相似文献   
42.
Radiological sign of chronic anterior cruciate ligament deficiency   总被引:1,自引:0,他引:1  
An early radiological sign of anterior cruciate ligament deficiency is described. A retrospective study of the radiographs of 38 patients with chronic anterior cruciate ligament deficiency was performed. In 36 patients from this group an osteophyte was present on the medial femoral condyle adjacent to the medial tibial spine. This was best seen on a 30 ° notch view and was the earliest radiographic sign of chronic anterior cruciate ligament deficiency.  相似文献   
43.
44.
45.
The pattern electroretinogram was recorded to checkerboard stimuli with a wide range of check sizes and two stimulus field sizes. Check sizes ranged from 0.25° to 7° (field size, 16°×14°) and 0.25° to 15° (field size, 32°×27°) in 14 and seven subjects, respectively. Reversal rate was 4.5/s. For minimal intrusion of blink artifacts the interrupted stimulation technique was employed. The P50 and N95 components of the pattern electroretinogram were evaluated separately. With both stimulus field sizes amplitude of P50 and N95 was maximal between 0.75° and 1°. With smaller check sizes the amplitude dropped monotonically. With larger check sizes field size played a role: with the 16°×14° field, P50 gradually dropped to 89% from 1° to 7°, which was paralleled by N95 only up to 7°, where N95 dropped to 81% (p<0.05). With the 32°×27° field, there was no significant difference in size dependency between P50 and N95 for large checks, both components staying constant from 1° to 15° We conclude that there is only minor large-check attenuation of the pattern electroretinogram, especially with a large field. The apparent field-size dependency may explain previous discrepancies in the literature.  相似文献   
46.
47.
920 cGy total body irradiation (TBI) is adequate for consistently successful engraftment of marrow from dog leukocyte antigen (DLA)-identical littermates; however, the dose is inadequate to ensure a marrow graft from DLA-nonidentical unrelated donors. Such mismatched grafts are successful only after 1800 cGy, given in three fractions. While anti-T-cell reagents enhance engraftment of DLA-identical littermate marrow after 920 cGy, they fail to be effective in the DLA-nonidentical setting. However, a monoclonal antibody (mAb) to CD44, S5, was found to be very effective in enhancing engraftment of DLA-nonidentical marrow. The current study asked whether mAb S5 was also effective in the setting of DLA-identical littermate transplants. To this purpose, the TBI dose was lowered to 450 cGy, a dose after which 70% of such grafts failed. Four dogs were treated with antibody S5, 0.2 mg/kg on days −7 though −2 (per previously published protocol), given 450 cGy TBI followed by marrow grafts from their DLA-identical littermates. All four dogs rejected their grafts; two of these died from marrow aplasia, and two survived with endogenous marrow recovery. This result was not statistically significantly different from that in 17, historical (n = 5) and concurrent (n = 12), control dogs where 11 of 17 animals rejected. Even if ten experimental animals were transplanted and all six remaining dogs engrafted, the results still would not have been significantly different from control. This result is in contrast to the successful engraftment promoted by pretreatment with antibody S5 of DLA-nonidentical unrelated dogs, consistent with the notion that different host cells are involved in graft rejection in the two disparate histocompatibility settings.  相似文献   
48.
49.
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