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   789篇
  免费   13篇
  国内免费   5篇
工业技术   807篇
  2023年   3篇
  2021年   11篇
  2020年   2篇
  2019年   8篇
  2018年   7篇
  2017年   5篇
  2016年   11篇
  2015年   10篇
  2014年   10篇
  2013年   17篇
  2012年   21篇
  2011年   25篇
  2010年   17篇
  2009年   24篇
  2008年   33篇
  2007年   32篇
  2006年   21篇
  2005年   31篇
  2004年   24篇
  2003年   20篇
  2002年   11篇
  2001年   22篇
  2000年   17篇
  1999年   28篇
  1998年   111篇
  1997年   63篇
  1996年   51篇
  1995年   27篇
  1994年   25篇
  1993年   23篇
  1992年   15篇
  1991年   11篇
  1990年   6篇
  1989年   7篇
  1988年   5篇
  1986年   4篇
  1985年   6篇
  1984年   2篇
  1983年   7篇
  1982年   2篇
  1980年   4篇
  1977年   2篇
  1976年   13篇
  1974年   1篇
  1972年   2篇
  1967年   1篇
  1965年   1篇
  1964年   1篇
  1957年   1篇
  1955年   1篇
排序方式: 共有807条查询结果,搜索用时 281 毫秒
91.
Tumor necrosis factor-alpha (TNF-alpha) levels were measured in the serum (sTNF-alpha) or bone marrow (BM) biopsies of 43 patients with myelodysplastic syndromes (MDS) who subsequently received therapy with a combination of pentoxifylline and ciprofloxacin (PC) with or without dexamethasone (PCD). All 43 patients received only PC therapy for 12 weeks, after which 18 of 36 nonresponders received PCD. A total of 18 of 43 patients showed a hematologic or cytogenetic response or both. BM TNF-alpha levels were semiquantitatively assessed using immunohistochemistry on a scale of 0-8+ and in the serum using enzyme linked immunoassay. The median TNF-alpha for the entire group was 3.0 in BM and 6.9 pg/ml in the serum, and 14 patients had no detectable levels. Responders had higher BM levels (median 3.5 vs. 2.0) than nonresponders, although this was not statistically significant. During PC therapy, a decline in BM TNF-alpha level was seen in the entire group, which was significant at 2 weeks (p = 0.02), 8 weeks (p = 0.001), and 12 weeks (p = 0.0001). Both responders (p = 0.01) and nonresponders (p = 0.03) had a decline at 8 weeks, but at 12 weeks, only the responders continued to show a significant decline (p = 0.03). We conclude that MDS patients with high BM TNF-alpa levels have a better chance of responding to PCD therapy and that the therapy is quite successful in reducing the TNF-alpha levels in a sustained fashion. Future studies need to be directed at identifying agents that would be more potent suppressors of the proapoptotic cytokines in these patients.  相似文献   
92.
93.
The effect of a single dose of morphine (50 mg/kg) and ethanol (2 g/kg) on total magnesium content in blood serum, brain, heart, lung, kidney, liver, femoral muscle and spleen in mice was studied. Significant decrease of magnesium serum concentration was observed after morphine and ethanol administration but not after both drugs given simultaneously. Morphine caused the evident decrease of magnesium content in brain, lung, kidney and muscle, while it was elevated in heart and spleen and unchanged in liver. Ethanol produced significant decrease of magnesium content in heart, lung and kidney and it's increase in liver and spleen. Concomitant administration of both drugs was connected with the diminished amount of magnesium in heart, lung, kidney and muscle and led to the rising of magnesium content in spleen. It is concluded that even a single dose of investigated drugs is sufficient to produce promptly some risk of alterations in magnesium homeostasis.  相似文献   
94.
Effects of prenatal corticosteroid on the properties of surfactant have not previously been evaluated. A single ultrasound-guided fetal injection with 0.5 mg/kg betamethasone 48 h before delivery of preterm lambs at 134- to 135-days gestation improved oxygenation, lowered the ventilatory pressures required to maintain arterial PCO2 between 30 and 40 Torr and decreased the protein leak of albumin from the intravascular to the alveolar space. This dose of glucocorticoid did not alter surfactant-saturated phosphatidylcholine pool sizes in the airspaces of preterm lambs. However, the treatment changed the characteristics of the surfactant recovered from the ventilated preterm lambs. The in vitro conversion from heavy to light subtype surfactant decreased from 59% for the saline-treated lambs to 37% for the corticosteroid-treated lambs after 180 min of surface area cycling (P < 0.02). Surfactant from the corticosteroid-treated lambs also increased the dynamic compliance of preterm surfactant-deficient rabbits more than did surfactant from the saline-treated lambs (P < 0.05). Prenatal treatment of preterm lambs with betamethasone improved the functional characteristics of surfactant without significant effects on the alveolar surfactant pool sizes.  相似文献   
95.
Pyriform sinus cyst and fistula is a relatively rare tumor of the neck, even less is the neonatal period. We experienced a case of this one, and preoperative diagnosis was made by using endoscopy and cine-esophagography. A dyeing method that confirmed the fistula tract of cyst lead us to successful resection.  相似文献   
96.
Three cases are reported who received brachytherapy with external irradiation for inoperable lung cancer and have shown long-term remission. The diseases were adenoid cystic carcinoma, recurrent adenocarcinoma and squamous cell carcinoma. The associated symptoms were severe cough and dyspnea in all 3 cases. They received 60 Gy of external irradiation. After an interval of 2 weeks, 6 Gy at a radius of 1 cm from the center of the source was delivered by iridium-192. They received 2-4 fractions at 1-week intervals. On termination of brachytherapy, complete response was observed in all cases. In 1 case, bronchial stenosis due to radiation-induced fibrosis was observed, but was successfully treated by bronchial stent. Cough and dyspnea disappeared, and all patients have been rendered asymptomatic for the last 2 years. Local disease was well controlled in 2 cases; however, minimal local recurrence was observed after a 2-year follow-up in 1 case.  相似文献   
97.
We have developed high-performance strained-SOI CMOS devices on thin film relaxed SiGe-on-insulator (SGOI) substrates with high Ge content (25%) fabricated by the combination of separation-by-implanted-oxygen (SIMOX) and internal-thermal-oxidation (ITOX) techniques without using SiGe buffer structures. The maximum enhancement of electron and hole mobilities of strained-SOI devices against the universal mobility amounts to 85 and 53%, respectively. On the other hand, we have also observed the reduction of carrier mobility in a thinner strained-Si layer or at higher vertical electric field conditions. For the first time, we have demonstrated a high-speed CMOS ring-oscillator using strained-SOI devices, and its improvement amounts to 63% at the supply voltage of 1.5 V, compared to control-SOI CMOS.  相似文献   
98.
99.
Cutaneous sarcomas are uncommon tumors presenting many histological types. The diagnosis is based on pathological, immunohistochemical and sometimes ultrastructural studies. The development of cytogenetic and molecular analysis may constitute an additional aid to the diagnosis and classification. Prognosis and therapeutic strategies are established on the basis of various criteria using different types of staging and grading, but these classifications have not yet been standardized. The rarity of cutaneous sarcoma, and the diversity of clinical presentations account for the difficulties of management, which requires a multidisciplinary approach.  相似文献   
100.
The antitumor activities of recombinant human tumor necrosis factor-alpha (rH-TNF alpha) and liposome-entrapped rH-TNF alpha were evaluated in various glioma cell lines and a rat brain T9 gliosarcoma model. rH-TNF alpha had a direct cytotoxic activity against various glioma cell lines in vitro, and indirect cytotoxic activity against gliosarcoma (T9) in vivo. Liposome-entrapped rH-TNF alpha had increased direct cytotoxic activity in vitro, and against experimentally induced brain tumors in vivo. The effects in vivo were probably due to vascular damage of the tumor vessels as shown by histological examination and activation of cytotoxic macrophages as shown in vitro. These results indicate that the general or local administration of liposome-entrapped rH-TNF alpha may become a useful adjunct treatment for malignant brain tumor.  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