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   33313篇
  免费   2005篇
  国内免费   335篇
耳鼻咽喉   541篇
儿科学   350篇
妇产科学   464篇
基础医学   5538篇
口腔科学   876篇
临床医学   2677篇
内科学   6255篇
皮肤病学   1315篇
神经病学   2488篇
特种医学   2235篇
外国民族医学   1篇
外科学   4158篇
综合类   167篇
一般理论   5篇
预防医学   1555篇
眼科学   578篇
药学   3325篇
中国医学   445篇
肿瘤学   2680篇
  2023年   172篇
  2022年   579篇
  2021年   1240篇
  2020年   563篇
  2019年   798篇
  2018年   978篇
  2017年   800篇
  2016年   1163篇
  2015年   1537篇
  2014年   1812篇
  2013年   2069篇
  2012年   3106篇
  2011年   3032篇
  2010年   1733篇
  2009年   1524篇
  2008年   2116篇
  2007年   1905篇
  2006年   1698篇
  2005年   1571篇
  2004年   1216篇
  2003年   1062篇
  2002年   900篇
  2001年   787篇
  2000年   720篇
  1999年   511篇
  1998年   201篇
  1997年   129篇
  1996年   114篇
  1995年   78篇
  1994年   90篇
  1993年   74篇
  1992年   145篇
  1991年   153篇
  1990年   172篇
  1989年   133篇
  1988年   119篇
  1987年   110篇
  1986年   93篇
  1985年   64篇
  1984年   43篇
  1983年   38篇
  1982年   28篇
  1981年   36篇
  1979年   23篇
  1978年   22篇
  1977年   23篇
  1975年   18篇
  1974年   17篇
  1972年   15篇
  1970年   23篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
161.
Son BH  Choi JS  Lee JH 《Pathology》2005,37(2):131-136
AIMS: To investigate KAI1 and survivin expression in infiltrating ductal carcinomas, and to evaluate the relationship between clinicopathological factors and KAI1 and survivin expression levels in breast cancers. METHODS AND RESULTS: KAI and survivin expression levels were measured in 62 patients, using immunohistochemical staining. Western blot analysis was performed on eight frozen cases. DNA ploidy was determined by flow cytometry. The results of the KAI1 expression analyses were as follows: in 14 cases (22.6%) levels were preserved (++), in 30 cases (48.4%) levels were reduced (+), in 18 cases (29.0%) no KAI1 expression was detected, so these were designated 'lost' (-). Results of assessments of survivin expression were as follows: six cases (9.7%) were strong positive (++), 28 cases (45.15%) were positive (+), and 28 cases (45.15%) were negative. Survivin (p=0.0009) and KAI1 (p=0.0091) expression levels were directly correlated with survival rate. However, no significant difference was determined to exist between survivin and KAI1 expression levels and the clinicopathological factors. DNA ploidy did not correlate with survivin and KAI1 expression levels and survival rate. Four different groups, according to their survivin and KAI1 expression levels, correlated with the clinical stage and survival rate. CONCLUSION: KAI1 and survivin expression levels might be prognostic factors in breast cancers.  相似文献   
162.
The ethanol extract of potato tubers (Solanum tuberlosum L.) has been evaluated for antinociceptive and anti-inflammatory activities in mice. The acute treatment of mice with an ethanolic extract from the potato tuber at doses of 100 and 200 mg/kg, by oral administration, produced a significant anti-nociceptive effect in the acetic acid-induced writhing, formalin-induced pain licking and hot plate-induced pain. Also, the ethanolic extract of potato tubers significantly inhibited both carrageenan- and formalin-induced inflammation in mice as well as arachidonic acid-induced ear edema in mice. These inhibitions were statistically significant (p<0.05). These results provide support for the use of the ethanol extract of potato tuber in relieving inflammatory pain, and insight into the development of new agents for treating inflammatory diseases.  相似文献   
163.
Transjugular intrahepatic portosystemic shunt (TIPSS) is a promising method of treatment for gastric or esophageal variceal bleeding. This study was performed to determine the prognostic factors contributing to the survival of patients after TIPSS for gastric or esophageal variceal bleeding. One hundred and fifty-five patients who underwent TIPSS between September 1991 and March 2001 were followed up by clinical examination, upper gastrointestinal endoscopy, and Duplex sonography. The mean portohepatic pressure gradient prior to TIPSS was 20.5+/-9.93 mmHg and dropped to 10.7+/-6.62 mmHg after TIPSS (p<0.001). The cumulative survival rate was 75.1% at 6 months, 66.6% at 1 yr, 58.4% at 2 yr, and 38.1% at 5 yr. Survival after TIPSS was inversely related to the Child-Pugh classification (p<0.05). The rebleeding rate was 18.3% at 6 months, 21.0% at 1 yr, 32.8% at 2 yr, and 53.1% at 5 yr. The causes of deaths were hepatic failure (53.5%), recurrent variceal bleeding (11.6%), pneumonia (4.6%), sepsis (3.5%), hepatic encephalopathy (2.3%), and unknown (17.4%). Multivariate analysis (Cox proportional hazard model) revealed that the Child-Pugh classification and age were statistically significant independent prognostic factors. In conclusion, TIPSS is an effective method of treatment for variceal bleeding in cases where other treatment modalities including endoscopic therapy are unsuccessful and the most important prognostic factors are preprocedural hepatic reserve (Child-Pugh class) and age.  相似文献   
164.
Angiogenesis and lymphangiogenesis are essential for breast cancer progression and are regulated by vascular endothelial growth factors (VEGF). To determine clinical and molecular correlates of these processes, we measured blood and lymphatic vascular microvessel density in 29 invasive carcinomas (22 ductal, six lobular, one papillary), using the vascular marker CD31 and the novel lymphatic marker D2-40. Microvessel density was assessed microscopically and by image cytometry, and was compared with tumor histology, grade, stage, lymph node metastasis, hormone receptors, HER2/neu status, and expression of VEGF, VEGF-C and VEGF-D by immunohistochemistry or quantitative RT-PCR. Strong correlation was observed between visual and image cytometric microvessel density using D2-40 but not CD31 (P=0.016 and 0.1521, respectively). Image cytometric CD31 microvessel density correlated with tumor size, grade, stage and lymph node metastasis (P=0.0001, 0.0107, 0.0035 and 0.0395, respectively). D2-40 microvessel density correlated with tumor stage (P=0.0123 by image cytometry) and lymph node metastasis (P=0.0558 by microscopy). Immunohistochemical VEGF signal in peritumoral blood vessels correlated with image cytometric CD31 and D2-40 microvessel density (P=0.022 and 0.0012, respectively), consistent with the role of VEGF in blood and lymphatic vascular growth. Intratumoral VEGF-C and VEGF-D expression by quantitative RT-PCR correlated with D2-40 (P=0.0291 by image cytometry) but not with CD31 microvessel density, which could suggest a selective role of VEGF-C and VEGF-D in lymphangiogenesis. CD31 and D2-40 microvessel density correlated significantly with several prognostic factors, including lymph node metastasis. Thus, measurements of angiogenesis and lymphangiogenesis may have utility for breast cancer pathology, particularly for estimation of metastatic risk.  相似文献   
165.
Choi SW  Roh KY  Chung KW  Kim MR 《Maturitas》2000,35(1):65-69
OBJECTIVES: This study was performed to determine whether skin pigmentation is darkened after hormone replacement therapy (HRT). METHODS: The color of hyperpigmentary lesions and control sites before and after 1, 2, and 3 months of HRT was measured. RESULTS: All of the three tested sites showed no significant pigment alteration in 3 months of follow up after starting HRT (P>0.05). Age, duration of menopause, and sex hormone levels did not correlate with pigmentation level. CONCLUSIONS: Pigmentation changes after HRT are not significantly associated with the treatment. This finding suggests that low-dose estrogen replacement therapy does not induce pigmentation changes alone and that differences in individual susceptibility and end organ responsiveness or other multiple factors in addition to the sex hormone may be responsible for the development and darkening of hyperpigmentary lesions.  相似文献   
166.
Pathogenicity of Treponema pallidum may depend upon the binding of Treponema pallidum to matrix proteins, especially to fibronectin. Infectious organism or cell to matrix interactions are mediated by a family of adhesion molecule receptors known as integrins. Once in the host, the pathogenic Treponema pallidumdum adheres to the vascular endothelium and readily penetrates surrounding tissues. Fibronectin plays an important role in the mediation of the attachment of Treponema pallidum to host cells, including endothelial cells. We found that the binding of Treponema pallidum to human dermal microvascular endothelial cells and to a glass surface coated with fibronectin is inhibited by the presence of arginine-glycine- aspartic acid (RGD), and analysis of the surface receptor revealed an antigenic similarity to an integrin molecule, namely alpha5. This ability to adhere to host endothelium and fibronectin is quite unique to T. pallidum among the treponemes, and may be a key pathogenic factor.  相似文献   
167.
A pectoralis quartus muscle and an unusual axillary arch were found on the left side of a female cadaver. The axillary arch was a musculoaponeurotic complex continuous with the iliacal fibers of the latissimus dorsi. The muscular part, together with the tendon of pectoralis major, inserted into the lateral lip of the bicipital groove of the humerus, whereas the aponeurotic part was formed by a fibrous band that extended deep to the pectoralis major to insert into the coracoid process between the attachments of the coracobrachialis and pectoralis minor. The pectoralis quartus originated from the rectus sheath, and joined the inferior medial border of the fibrous band of the axillary arch, at the lateral edge of the pectoralis major. The axillary arch muscle crossed anteriorly the axillary vessels and the brachial plexus. The clinical importance of these muscles is reviewed.  相似文献   
168.
We have used gene expression profiling approaches to identify new molecular targets in various models of lung injury and human lung diseases. Among the many genes that are significantly induced in these studies, cysteine-rich61 (Cyr61) consistently ranks as one of the most significant genes. Here, we use the well-established model of hyperoxia to better understand the function of Cyr61 in acute lung injury. Cyr61, a stress-related immediate-early response gene, has known diverse functions involving angiogenesis, tumorigenesis, and wound repair. It belongs to the newly discovered "CCN" family containing six growth and regulatory factors. We showed that hyperoxia induces Cyr61 expression in a variety of pulmonary cells and in lung tissue in vivo. Loss of function studies, by suppressing Cyr61 expression by siRNA, accelerated lung epithelial cell death after hyperoxia. Gain of function studies, by overexpressing Cyr61, significantly conferred increased resistance to hyperoxia-induced cell death. Moreover, cells overexpressing Cyr61 induce Akt activation. Inhibition of Akt by siRNA abrogated the protective effects of Cyr61-overexpressing cells in response to hyperoxia. Taken together, our data demonstrate that Cyr61 expression provides cytoprotection in hyperoxia-induced pulmonary epithelial cell death and that this effect was in part mediated via the Akt signaling pathway.  相似文献   
169.
To better understand the pathophysiological role of Src protein, a non-receptor protein tyrosine kinase of 60kDa, in the ischemic brain, we investigated the time course and regional distribution of active Src expression by using a specific antibody against Tyr416 phosphorylated Src (phospho-Src) in the rat hippocampus after transient forebrain ischemia. In the hippocampus of the control animals, active Src expression was too low to be detected by immunolabeling. Beginning 4h after reperfusion, active Src expression became evident and, after 1 day, had increased preferentially in the CA field of the hippocampus proper and the dentate gyrus. By day 3, active Src expression markedly increased in the pyramidal cell layer of CA1 and the dentate hilar region in temporal correlation with neuronal cell death occurring in these areas, where cells typical of phagocytic microglia showed phospho-Src immunoreactivity. Double-labeling experiments revealed that cells expressing active Src were microglia that stained for biotinylated lectin derived from Griffonia simplicifolia (GSI-B4). Active Src expression began to decline at day 7 and returned to the basal level by day 14 after reperfusion. These results demonstrate increased phosphorylation of Src in activated microglia of the post-ischemic hippocampus, indicating that Src signaling may be involved in the microglial reaction to an ischemic insult.  相似文献   
170.
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