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   413851篇
  免费   21443篇
  国内免费   14444篇
耳鼻咽喉   3320篇
儿科学   9541篇
妇产科学   7835篇
基础医学   44261篇
口腔科学   5755篇
临床医学   43208篇
内科学   69893篇
皮肤病学   3466篇
神经病学   29558篇
特种医学   17368篇
外国民族医学   98篇
外科学   54820篇
综合类   36522篇
现状与发展   50篇
一般理论   45篇
预防医学   32957篇
眼科学   9401篇
药学   33500篇
  177篇
中国医学   11603篇
肿瘤学   36360篇
  2024年   716篇
  2023年   3511篇
  2022年   8739篇
  2021年   11510篇
  2020年   8467篇
  2019年   7640篇
  2018年   29165篇
  2017年   23804篇
  2016年   25609篇
  2015年   11008篇
  2014年   13564篇
  2013年   12692篇
  2012年   24316篇
  2011年   39671篇
  2010年   30069篇
  2009年   20651篇
  2008年   31855篇
  2007年   34121篇
  2006年   12960篇
  2005年   14608篇
  2004年   11885篇
  2003年   11897篇
  2002年   9089篇
  2001年   6304篇
  2000年   6574篇
  1999年   6639篇
  1998年   3884篇
  1997年   3919篇
  1996年   2907篇
  1995年   2701篇
  1994年   2335篇
  1993年   1563篇
  1992年   2331篇
  1991年   2086篇
  1990年   1794篇
  1989年   1534篇
  1988年   1319篇
  1987年   1218篇
  1986年   970篇
  1985年   778篇
  1984年   510篇
  1983年   402篇
  1982年   249篇
  1981年   203篇
  1980年   231篇
  1979年   245篇
  1978年   149篇
  1977年   115篇
  1976年   105篇
  1974年   135篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
91.
92.
神经肽Y(NPY)是广泛分布于中枢神经系统和外周神经各部位的神经肽类物质。本实验观察NPY在体外对几种免疫细胞活性的直接作用。结果表明,NPY对小鼠T淋巴细胞丝裂原反应性和NK细胞的杀伤活性均无明显影响(P>0.05),对巨噬细胞分泌溶菌酶有明显抑制作用(P<0.05);而对B淋巴细胞丝裂原反应性则有明显的促进作用(P<0.05)。上述结果提示,NPY对部分免疫细胞功能的影响因细胞种类而异。  相似文献   
93.
The MR imaging features of a paraganglioma of the cauda equina with associated spinal cord cysts are presented. MR imaging showed the tumor to be isointense with the spinal cord on all pulse sequences and to enhance homogeneously. The intramedullary cysts had increased signal intensity on proton density- and T2-weighted images, and involved the cervical and thoracic regions.  相似文献   
94.
95.
斑点—酶联免疫吸附试验检测卡氏肺孢子虫   总被引:1,自引:0,他引:1  
应用完整的卡氏肺孢子虫包囊作抗原,以4×10^7/ml包裹点样,作斑点-酶联免疫吸附试验检测肺印片卡氏肺孢子虫包囊阳性的BALB/c小鼠血清20份,同时检测包囊阴性的小鼠血清20份,结果除一份小鼠血清IgG阴性反应外,均为阳性反应,阳性率为95%;而正常对照血清全为阴性反应。另外,检测了3份纤支镜刷检物中包囊阳性的病人血清,均为阳性反应;50例健康孕妇血清的检查,抗体阳性率为12%。  相似文献   
96.
The granulocyte colony-stimulating factor (G-CSF) has been shown to accelerate recovery from severe neutropenia and to decrease the incidence of documented infections after intensive chemotherapy in cancer patients. However, the routine prophylactic use of G-CSF is expensive. This study was conducted to determine the role of G-CSF as adjunct therapy for septicemia following neutropenia caused by chemotherapy in children with acute leukemia. Fifty consecutive episodes of septicemia were studied involving 34 episodes of Gram-negative, 7 episodes of Gram-positive, 5 episodes of polymicrobial bacterial septicemia, one episode of fungemia, and 3 episodes of disseminated fungal infection. In the first 25 episodes, G-CSF was not used (group A). For the next 16 episodes, G-CSF 200 μg per square meter per day subcutaneously was given immediately after the septicemia was documented until the absolute neutrophil count was maintained at more than 1,500 per cubic millimeter (group B). Thereafter, G-CSF at the same dose as that of group B was prophylactically used in all the children who received high-dose cytosine arablnc-side-containing regimens. Nine episodes of septicemia occurred (group C). The incidences of mortality per episode of septicemia in groups A, B, and C were 12.0% (3/25), 12.5% (2/16) and 0% (0/9), respectively. Statistically, there was no difference between the three groups overall and in pair-wise comparisons (all P > 0.5). The durations of G-CSF administration in group B ranged from 6 to 26 days with a median of 12 days and the durations of G-CSF administration in group C ranged from 10 to 23 days with a median of 19 days. With or without G-CSF, there may be no significant difference in the mortality of septicemia following neutropenia caused by chemotherapy in children with acute leukemia.  相似文献   
97.
Twenty-two infants of isolated ventricular septal defect with congestive heart failure were fed with lower-sodium content formula-Lonalac (Mead-Johnson) to study the clinical response of treatment for congestive heart failure. There were no significant changes of intake, urinary output, serum sodium, potassium and osmolality before, 2 days and 6 days after Lonalac feeding. The low sodium content formula may feed the infants with congestive heart failure in addition to the traditional anticongestive therapy.  相似文献   
98.
股骨颈骨折粗细双螺钉内固定生物力学研究   总被引:3,自引:0,他引:3  
股骨颈骨折内固定方法繁多。本文采用一粗一细加压螺纹钉,采用先进电阻应变仪方法,对股骨颈的应力分布规律在中立、外展、内收不同位置上施加50kg荷载压力.通过电阻应变计测定一耗一细两钉所承受拉、压应力优于其它内固定形式。  相似文献   
99.
Ductal adenoma of the breast   总被引:1,自引:0,他引:1  
Ductal adenoma is a recently described benign tumour of the breast that can be mistaken for carcinoma in both frozen and paraffin sections. Such a case is presented. Fortunately a mastectomy was not performed, but the patient did undergo axillary node dissection. Surgeons and pathologists should familiarize themselves with this lesion so that patients do not have to undergo unnecessary mastectomies and axillary node dissections.  相似文献   
100.
The hereditary characteristics of enzyme deficiency and dermatoglyphics in congenital color blindness (CCB) were studied. We propose that there is a linkage between the two loci on the X-chromosome determining CCB and glucose-6-phosphate dehydrogenase (G6PD), based on our study of a high incidence of G6PD deficiency in 156 male cases with CCB. The CCB gene is closely linked with that of G6PD deficiency from our pedigree investigations. The rise in the frequency of eight or more whorls, the low value of atd angle and the presenting rate of real palmar patterns of the thenar, hypothenar and I, areas presented the hereditary traits of congenital color blindness.  相似文献   
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