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   97116篇
  免费   8444篇
  国内免费   3512篇
耳鼻咽喉   1332篇
儿科学   1803篇
妇产科学   1737篇
基础医学   12704篇
口腔科学   1766篇
临床医学   10989篇
内科学   18244篇
皮肤病学   1690篇
神经病学   6152篇
特种医学   4114篇
外国民族医学   22篇
外科学   12029篇
综合类   7649篇
现状与发展   13篇
一般理论   40篇
预防医学   5588篇
眼科学   2989篇
药学   8779篇
  38篇
中国医学   2796篇
肿瘤学   8598篇
  2024年   209篇
  2023年   1170篇
  2022年   2733篇
  2021年   4153篇
  2020年   2931篇
  2019年   2980篇
  2018年   3229篇
  2017年   2755篇
  2016年   2874篇
  2015年   3918篇
  2014年   4699篇
  2013年   4884篇
  2012年   6979篇
  2011年   7355篇
  2010年   4494篇
  2009年   3637篇
  2008年   5184篇
  2007年   5213篇
  2006年   5033篇
  2005年   4771篇
  2004年   3862篇
  2003年   3523篇
  2002年   3047篇
  2001年   2398篇
  2000年   2317篇
  1999年   2199篇
  1998年   1041篇
  1997年   931篇
  1996年   754篇
  1995年   667篇
  1994年   609篇
  1993年   434篇
  1992年   932篇
  1991年   830篇
  1990年   811篇
  1989年   739篇
  1988年   679篇
  1987年   644篇
  1986年   567篇
  1985年   462篇
  1984年   333篇
  1983年   258篇
  1982年   148篇
  1981年   141篇
  1980年   132篇
  1979年   201篇
  1978年   132篇
  1977年   109篇
  1976年   125篇
  1975年   113篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
INTRODUCTION: The first-order kernel response of multifocal electroretinogram (mfERG) decreases in myopia. A recent study indicates that the flash ERG is also reduced with increased axial length. The aim of this study was to investigate the variations in the first-order response (K1) and the first slice of second-order response (K2.1) across the retina for different axial lengths. METHODS: Thirty healthy subjects with axial length from 23.72 to 28.13 mm (spherical equivalent refractive errors from plano to -10.50 D) were recruited for mfERG measurement using VERIS 4.0. All subjects were fully corrected after cycloplegic refraction and pupils were dilated prior to mfERG recording. There is one trough, n1, and one peak, p1, in the K1 response and three troughs, n1, n2, n3, and three peaks, p1, p2, p3, in the K2.1 response. The amplitudes and implicit times of K1 and K2.1 responses were analysed to determine the characteristic of the responses across retina and the correlation to axial length. RESULTS: The amplitudes of p1 (in the first-order kernel-K1) decreased in the central region and the paracentral region (ring 3) as the axial length increased. The central retinal region showed high rates of reduction in both n1 and p1 (in K1). The amplitudes of n1p1 and n2p2 (in the first slice of the second-order kernel-K2.1) were reduced in the paracentral region (from ring 2 to ring 5) as axial length increased. The average n1 and p1 in K1, and n1p1 and n2p2 in K2.1 mfERG responses are decreased in amplitude by 6-10% per millimetre elongation of axial length. CONCLUSION: Eyes with longer axial lengths, usually with high myopia, have a weaker mfERG response and this attenuation is across the measured retina (from central to paracentral regions) but different kernel responses show a different pattern of attenuation at different retinal eccentricities. The weaker mfERG responses may be related to the morphological changes associated with increased axial length.  相似文献   
82.
83.
84.
K. L. Chan 《Hernia》2007,11(1):37-40
Background Open repair of recurrent paediatric inguinal hernias (IH) is difficult and there is definite risk of damaging the vas deferens and testicular vessels during dissection of the previous open herniotomy field. Laparoscopic repair (LR) has the benefit of avoiding the previous operative site. Method Records of patients with recurrent IH that had LR after open repair were reviewed and evaluated retrospectively. The results were compared with data from cases in which the LR method was used in the initial IH repair. Results From September 2002 to October 2005, four boys and one girl (mean age 58.8 months) were treated in our institution for recurrent IH after open repair. Operative time, success rate and complications did not show any statistically significant difference when compared with our previous prospectively collected data for primary repairs. Conclusion Laparoscopic repair is the preferred operation for recurrent childhood IH after open repair.  相似文献   
85.
86.
AIM To clone novel gastric cancer-associated genes and investigate their roles in gastric cancer occurrence.METHODS A method called differential display was used which allows the identification of differentially expressed genes by using PAGE to display PCR-amplified cDNA fragments between gastric cancer cells and normal gastric mucosa cells. These fragments were cloned into plasmid vector pUC18. Homology analysis was made after sequencing these fragments.RESULTS Two novel genes were identified compared with sequences from GenBank. One was registered with the AD number AF 051783. In situ hybridization showed that these two novel genes expressed specifically in gastric cancer tissues.CONCLUSION The two novel genes obtained by differential display were confirmed to be gastric cancer-associated genes using in situ hybridization.  相似文献   
87.
We have reported a case of idiopathic hypereosinophilic syndrome (HES) with polymyositis, in which there was marked eosinophilic leukocytic infiltration of the myocardium and striated skeletal muscles, particularly of the diaphragm, with foci of necrosis and areas of fibrosis. We believe this to be the first detailed report of the involvement of the diaphragm in HES.  相似文献   
88.
We report a case of congenital fistula from ectopic accessory parotid gland to the cheek demonstrated by CT sialography and CT fistulography. The right parotid gland was abnormally located lateral to masseter muscle. The fistula was arising from an ectopic accessory parotid gland with ectopic duct positioned anterior to masseter muscle. CT sialography and CT fistulography were very helpful in the diagnosis and surgical planning.  相似文献   
89.
As it is not known what changes to leucocyte homeostasis are mandatory for effective adjuvant action, the biological relevance of systemic changes elicited by different vaccine formulations can only be interpreted in the context of the immunological outcomes. We used flow cytometry to quantify the changes in leucocyte subsets induced in mice intradermally immunized with SAMA4 (adjuvant group), outer membrane proteins (OMP) purified from Actinobacillus pleuropneumoniae (OMP antigen group), SAMA4 adjuvanted OMP (OMP vaccine group), or phosphate-buffered saline (PBS: control group). This approach allowed direct comparisons to be made between the effects of antigen, adjuvant or antigen–adjuvant complexes on immune effector cell populations. Antigens complexed with the liposome–iscom hybrid adjuvant, SAMA4, generated strong antibody responses and cytotoxic T-cell activity in animals immunized intradermally, reflecting remobilization and recruitment of specific cell populations. Splenomegaly, due to granulocytosis, monocytosis and megakaryocytosis, was most prominent in the OMP vaccine group. Histological examination of spleen sections confirmed that these changes were due primarily to splenic haematopoiesis. Circulating numbers of granulocytes and monocytes increased significantly (P < 0.05) in the blood of the OMP vaccine group, as did granulocyte numbers in the lungs (P < 0.05). No changes in T- and B-cell numbers were detected by flow cytometry in the spleens, lungs or blood over the 28-day period in any treatment group. Thymocyte numbers (predominantly CD4+CD8+ cells) in the OMP vaccine group fell by 95% within 3 days of immunization. Identical cellular responses were obtained when an innocuous antigen, ovalbumin, was complexed with SAMA4 instead of OMP, thus demonstrating that the adjuvant effects of SAMA4 were due to synergistic interaction between antigen and adjuvant and not due to the presence of toxic components. The association of strong adaptive immune responses with such complex changes in leucocyte homeostasis induced by complexing adjuvant and antigen suggested that the changes were important for effective vaccination and were not purely circumstantial.  相似文献   
90.
Trisomy 8 and, less commonly tetrasomy 8, are karyotypic aberrations found in myeloid malignancies. We describe a unique case of acute myeloid leukemia with partial pentasomy 8 resulting from duplication of isochromosome 8q, and discuss its possible roles in leukemogenesis.  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