首页 | 官方网站   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   7411篇
  免费   332篇
  国内免费   40篇
医药卫生   7783篇
  2023年   38篇
  2022年   55篇
  2021年   196篇
  2020年   93篇
  2019年   113篇
  2018年   159篇
  2017年   119篇
  2016年   153篇
  2015年   174篇
  2014年   222篇
  2013年   304篇
  2012年   436篇
  2011年   499篇
  2010年   285篇
  2009年   224篇
  2008年   394篇
  2007年   433篇
  2006年   404篇
  2005年   378篇
  2004年   430篇
  2003年   397篇
  2002年   398篇
  2001年   142篇
  2000年   174篇
  1999年   137篇
  1998年   107篇
  1997年   108篇
  1996年   90篇
  1995年   69篇
  1994年   66篇
  1993年   46篇
  1992年   90篇
  1991年   78篇
  1990年   64篇
  1989年   68篇
  1988年   62篇
  1987年   65篇
  1986年   48篇
  1985年   76篇
  1984年   47篇
  1983年   29篇
  1982年   24篇
  1981年   25篇
  1980年   32篇
  1979年   24篇
  1978年   20篇
  1976年   18篇
  1975年   18篇
  1973年   19篇
  1969年   18篇
排序方式: 共有7783条查询结果,搜索用时 15 毫秒
81.
The aim of this research was to reveal the characteristics of gut microbiome altered by acarbose intervention in Japanese patients with type 2 diabetes (T2D) and its possible association with habitual dietary intake. Eighteen patients with T2D were administered acarbose for four weeks. The abundances of two major phyla, namely Actinobacteria and Bacteroidetes, were reciprocally changed accompanied by the acarbose intervention. There were also significant changes in the abundances of ten genera, including the greater abundance of Bifidobacterium, Eubacterium, and Lactobacillus and the lower abundance of Bacteroides in the group after the intervention than that before the intervention. Hierarchical clustering of habitual dietary intake was performed based on the pattern of changes in the gut microbiota and were classified into distinct three clusters. Cluster I consisted of sucrose, cluster II mainly included fat intake, and cluster III mainly included carbohydrate intake. Moreover, the amount of change in Faecalibacterium was positively correlated with the intake of rice, but negatively correlated with the intake of bread. The intake of potato was negatively correlated with the amount of change in Akkermansia and Subdoligranulum. Acarbose altered the composition of gut microbiome in Japanese patients with T2D, which might be linked to the habitual dietary intake.  相似文献   
82.
83.
84.
Purpose: To examine the deposition of extracellullar matrix on silicone intraocular lenses (IOLs) implanted experimentally into rabbit eyes by electron microscopy and to determine the immunolocalization of extracellular matrix components, including collagen types and cellular fibronectin, on these IOLs. Methods: We performed phacoemulsification and aspiration of the crystalline lens and implanted a foldable silicone IOL in the capsular bag of one eye of each of 26 adult albino rabbits under general anesthesia. After 8 weeks the animals were killed and the eyes were enucleated. The silicone IOLs were processed for electron microscopy and for immunohistochemical detection of collagen types I, III, and IV and cellular fibronectin. Results: Electron microscopy revealed deposition of a presumed cell matrix complex on the optic portion of all silicone IOLs, as well as the adhesion of presumed macrophages and foreign-body giant cells. Cellular deposits showed immunoreactivity for cellular fibronectin. Fibrous or membranous deposits exhibited immunoreactivity for cellular fibronectin and collagen types I and III. A few type IV collagen-immunoreactive deposits were also seen. Conclusion: Deposits of extracellular matrix components were observed on silicone IOLs. These deposits may form the scaffolding for the adhesion and proliferation of cells. These matrix components appeared to be the products of cells adhering to the surfaces of IOLs, including lens epithelial cells, macrophages and foreign-body giant cells, indicating that the process of granulation was incomplete.  相似文献   
85.
The incidence and clinicopathologic features of unilateral multicentric breast cancer (UMBC) were studied by mammary gland serial sectioning in 116 cases of clinically defined monocentric breast cancer (MONBC) examined histopathologically at the Nagano Cancer Detection Center. UMBC was defined as: 1) histopathologically discontinuous tumors each with an intraductal spread, 2) at least one tumor-free section separating two tumors, and 3) a large primary tumor and other small secondary tumors. UMBC was detected in 23 of 116 cases (19.8%), all with one secondary tumor. Primary and secondary tumors were located in the same quadrant in 34.8% and in different ones in 65.2%. The secondary tumors were <5 mm in size in 56.5%. Secondary tumors, averaging 8.3 mm in size and 25.5 mm in distance from the primary tumor, were almost exclusively noninvasive carcinomas, including 15 (65.4%) noninvasive ductal carcinomas and several special types. The primary and secondary tumors were of the same histologic type in 3 of 23 cases. UMBC patients averaged 6 years younger than MONBC patients, and the incidence of UMBC tended to be higher in younger patients (p<0.1). UMBC tended to occur more frequently in quadrant with an average histologie tumor size significantly smaller than that in MONBC (p<0.01). The histologie types of the primary tumor in UMBC and MONBC were similar, with common types predominant. Lymph node metastases tended to be slightly more frequent in MONBC. This high incidence of UMBC calls for careful attention when considering breast conserving therapy.  相似文献   
86.
Heart tissues of patients with PD or incidental Lewy body (LB) disease (ILBD) were examined by light and electron microscopy. LBs and alpha-synuclein-positive neurites were identified in the hearts from 9 of 11 patients with PD and from 7 of 7 patients with ILBD. LBs were present in both tyrosine hydroxylase-positive and -negative nerve processes, which are nerves of extrinsic sympathetic and intrinsic origin, respectively. These findings provide histologic evidence that the postganglionic sympathetic and intrinsic neurons in the heart are involved in the PD disease process.  相似文献   
87.
88.
Few studies have investigated the relation between glucose tolerance status and ultrasonographically determined gallstone disease. Using a 75-g oral glucose tolerance test, we examined the association of impaired glucose tolerance (IGT) and non-insulin-dependent diabetes mellitus (NIDDM) with gallstone disease in Japanese men. Subjects were men aged 48 to 59 of the Japan Self-Defense Forces who received a preretirement health examination between October 1986 to December 1994. After exclusion of 12 men under insulin treatment in the consecutive series of 7637 men, 174 were found to have gallstones; 103 were at the state of postcholecystectomy, and 6899 had normal gallbladder. IGT and NIDDM were associated with a modestly increased risk of gallstone disease; adjusted odds ratios were 1.3 (95% confidence interval [CI]: 0.9–1.8) for IGT and 1.3 (95% CI: 0.8–2.0) for NIDDM after adjustment for hospital, rank, smoking, alcohol use, and body mass index. Adjusted odds ratio for IGT and NIDDM combined was 1.3 (95% CI: 1.0–1.7, p=0.08). When prevalent gallstones and postcholecystectomy were considered separately, NIDDM showed a significant, positive association with postcholecystectomy, but not with prevalent gallstones. The findings add to evidence that glucose intolerance is associated with a modest increase in the risk of gallstone disease.  相似文献   
89.
PURPOSE: Peripheral nerve (PN) grafting to the optic nerve stump stimulates not only axonal regeneration of the axotomized retinal ganglion cells (RGCs) into the grafted PN but also their survival. The purpose of the present study was to determine the number, distribution, and soma diameter of only surviving RGCs without regenerated axons and surviving RGCs with regenerated axons in PN-grafted mammals. METHODS: A segment of PN was grafted to the optic nerve stump of adult ferrets. Two months after the PN grafting, surviving RGCs with regenerated axons were retrogradely labeled with granular blue (GB) and stained with RGC-specific antibody C38. Surviving RGCs without regenerated axons were identified as C38-positive cells without GB labeling. RESULTS: Twenty-one percent of RGCs survived axotomy after PN grafting in the area centralis (AC), whereas 47% survived in the peripheral retina. Twenty-six percent of surviving RGCs in the AC exhibited axonal regeneration, which was higher than that in the peripheral retina. Soma diameter histograms revealed that RGCs with regenerated axons showing both GB and C38 positivity were in the large soma diameter ranges. In contrast, the soma diameter distribution of surviving RGCs that did not have regenerated axons showed a peak in the smaller soma diameter ranges. CONCLUSIONS: The present data suggest that PN grafting promotes survival of axotomized RGCs more effectively in the peripheral retina than in the AC. Among surviving RGCs, the larger cells exhibited axonal regeneration into the grafted PN, whereas the axons of smaller cells did not to regenerate in either the AC or the peripheral retina.  相似文献   
90.
Background: The excessive accumulation of extracellular matrix (ECM) with the repopulation of fibroblasts may lead to an unsuccessful outcome of glaucoma filtering surgery. We examined the immunolocalization of ECM components and prolyl 4-hydroxylase, an enzyme involved in collagen biosynthesis, in cultured Tenon's capsule fibroblasts (TCFs) of humans to evaluate the production of ECM in the cells. Methods: We used light microscopy to evaluate the immunolocalization of prolyl 4-hydroxylase and ECM components, collagen types I, III, and IV, cellular fibronectin, and laminin in TCFs. Ultrastructural localization of the enzyme was also evaluated by electron microscopy. Results: Immunoreactivity with monoclonal antibodies against the and subunits of the enzyme or with the polyclonal antibody against it was detected in the cytoplasm of the cells in a fine granular pattern, indicating its localization in the indoplasmic reticulum (ER). Immunoreactivity for the enzyme was detected in the cisternae of the ER on electron microscopy. Types I and III collagen reactivities were also observed in the cytoplasm in a fine granular pattern. T reactivity was present diffusely on the cell surface. The distribution of laminin reactivity in the cytoplasm resembled that of types I and III collagen. Cellular fibronectin reactivity was observed in the ECM in a reticular pattern. Conclusion: Prolyl 4-hydroxylase was located in the cisternae of the ER. TCFs produced a variety of ECM components in vitro. The results provide insight into the fibrotic process during scar formation at the site of a bleb following filtering surgery.  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-23

京公网安备 11010802026262号