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   2642篇
  免费   157篇
  国内免费   11篇
耳鼻咽喉   19篇
儿科学   87篇
妇产科学   113篇
基础医学   430篇
口腔科学   207篇
临床医学   194篇
内科学   619篇
皮肤病学   46篇
神经病学   152篇
特种医学   80篇
外科学   218篇
综合类   3篇
一般理论   2篇
预防医学   123篇
眼科学   35篇
药学   180篇
中国医学   5篇
肿瘤学   297篇
  2023年   18篇
  2022年   32篇
  2021年   69篇
  2020年   47篇
  2019年   63篇
  2018年   77篇
  2017年   48篇
  2016年   64篇
  2015年   65篇
  2014年   93篇
  2013年   135篇
  2012年   154篇
  2011年   196篇
  2010年   99篇
  2009年   109篇
  2008年   179篇
  2007年   186篇
  2006年   145篇
  2005年   134篇
  2004年   120篇
  2003年   128篇
  2002年   94篇
  2001年   56篇
  2000年   40篇
  1999年   52篇
  1998年   19篇
  1997年   18篇
  1996年   9篇
  1995年   11篇
  1994年   11篇
  1993年   10篇
  1992年   22篇
  1991年   25篇
  1990年   18篇
  1989年   32篇
  1988年   16篇
  1987年   17篇
  1986年   18篇
  1985年   16篇
  1984年   18篇
  1983年   8篇
  1982年   9篇
  1981年   8篇
  1979年   14篇
  1978年   12篇
  1977年   9篇
  1975年   7篇
  1973年   15篇
  1972年   12篇
  1971年   7篇
排序方式: 共有2810条查询结果,搜索用时 15 毫秒
11.
Carbon tetrachloride (CCl4)-induced hepatic fibrosis has been considered to be linked to oxidative stress and mediated by aldehydic lipid peroxidation products. In the present study, we investigated whether collagen synthesis is induced by F2-isoprostanes, the most proximal products of lipid peroxidation and known mediators of important biological effects. By contrast with aldehydes, F2-isoprostanes act through receptors able to elicit definite signal transduction pathways. In a rat model of CCl4-induced hepatic fibrosis, plasma F2-isoprostanes were markedly elevated for the entire experimental period; hepatic collagen content also increased. When hepatic stellate cells (HSCs) from normal liver were cultured with F2-isoprostanes in the concentration range found in the in vivo studies (10(-9)-10(-8) M), a striking increase in DNA synthesis (reversed by the thromboxane A2 antagonist SQ 29 548), in cell proliferation and in collagen synthesis was observed. Total collagen content was similarly increased. Moreover, F2-isoprostanes markedly increased the production of transforming growth factor-beta1 by U937 cells, considered a model of liver macrophages. The data provide evidence for the possibility that F2-isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen production seen in hepatic fibrosis.  相似文献   
12.
Titanium (Ti) endosseous dental screws with different surfaces (smooth titanium--STi, titanium plasma-sprayed-TPS, alumina oxide sandblasted and acid-etched--Al-SLA, zirconium oxide sandblasted and acid etched--Zr-SLA) were implanted in femura and tibiae of sheep to investigate the biological evolution of the peri-implant tissues and detachment of Ti debris from the implant surfaces in early healing. Implants were not loaded. Sections of the screws and the peri-implant tissues obtained by sawing and grinding were analysed by light microscopy immediately after implantation (time 0) and after 14 days. All samples showed new bone trabeculae and vascularised medullary spaces in those areas where gaps between the implants and host bone were visible. In contrast, no osteogenesis was induced in the areas where the implants were initially positioned in close contact with the host bone. Chips of the pre-existing bone inducing new peri-implant neo-osteogenesis were surrounded by new bone trabeculae. The threads of some screws appeared to be deformed where the host bone showed fractures. Ti granules of 3-60 microm were detectable only in the peri-implant tissues of TPS implants both immediately after surgery and after 14 days, thus suggesting that this phenomenon may be related to the friction of the TPS coating during surgical insertion.  相似文献   
13.
14.
15.
Thirty-one patients with metastatic breast cancer not responding or progressing after initial response to adriamycin + cyclophosphamide (AC) treatment entered a phase 11 study with oral lonidamine in association to AC. Objective clinical responses were observed in 10 patients (32%) and consisted of 1 complete + 9 partial remissions. Disease stability and progression were observed in 8 and 13 cases, respectively. These results were obtained with a marginal toxicity in addition to that already reported for AC therapy, the main additional side effect being myalgia, which was easily manageable in most cases.  相似文献   
16.
A case of primary lymphoma of the liver in a 72-year-old man is reported. The patient showed a three to four month history of abdominal ache, low grade fever, and weight loss. The presence of a large mass occupying the V and VT hepatic segments was demonstrated; no other organs were involved and no evidence of lymphoadenopathy was found. Laboratory tests showed a remarkable increase in ESR, LDH and alkaline phosphatase while CEA and alpha-1 fetoprotein were within the normal values. Two ultrasound-guided needle biopsies on the hepatic lesion did not produce any significant tissue for diagnosis. Therefore the V and VI hepatic segments were excised; a hard, greyish mass with the largest diameter of 6.5 cm, was found at laparatomy. Histology of the surgical specimen showed the presence of a malignant non-Hodgking's B-cell lymphoma, centroblastic-centrocytic, diffuse type (working formulation: G) of intermediate grade of malignancy. Staging was completed with lymphography, and bone marrow biopsy; both proved normal. After the operation adjuvant chemotherapy was commenced (COP for six cycles). Follow-up has so far shown no signs of recurrence after 24 months. In conclusion, the diagnosis of primary lymphoma of the liver is very difficult and is often reached only after histologic evaluation of the surgical specimen. Moreover, this disease has a much more favourable prognosis than the hepatocellular carcinoma and other primary or secondary liver cancers; therefore accurate investigations are important to reach the correct diagnosis.  相似文献   
17.
18.
19.
20.
Recombinant activated factor VII (rFVIIa) was originally developed for the treatment of bleeding in patients with haemophilia A or B and inhibitors. Over the past ten years, it has been successfully used to prevent or control bleeding in several other nonhaemophilic bleeding conditions. Among the newer 'off-label' clinical applications of rFVIIa, there is increasing evidence of its effectiveness in treating obstetric and gynaecological bleeding unresponsive to conventional therapy. The existing literature on the use of rFVIIa in obstetrics and gynaecology is summarised in this review. Although supported by few and uncontrolled studies, on the whole, the published data suggest a potential role of rFVIIa in the management of obstetric and gynaecological intractable bleeding. However, further evidence is needed to improve the assessment of its optimal dose, effectiveness and safety in such conditions.  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