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   3294篇
  免费   2篇
电工技术   2篇
化学工业   40篇
金属工艺   5篇
机械仪表   1篇
建筑科学   2篇
矿业工程   2篇
能源动力   7篇
轻工业   24篇
无线电   6篇
一般工业技术   15篇
冶金工业   3176篇
原子能技术   4篇
自动化技术   12篇
  2021年   3篇
  2020年   3篇
  2019年   3篇
  2017年   4篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   13篇
  2012年   5篇
  2011年   4篇
  2010年   1篇
  2009年   3篇
  2008年   3篇
  2007年   9篇
  2006年   7篇
  2005年   5篇
  2004年   8篇
  2003年   8篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
  1999年   71篇
  1998年   925篇
  1997年   540篇
  1996年   392篇
  1995年   235篇
  1994年   162篇
  1993年   183篇
  1992年   20篇
  1991年   35篇
  1990年   27篇
  1989年   30篇
  1988年   25篇
  1987年   20篇
  1986年   20篇
  1985年   19篇
  1984年   1篇
  1983年   5篇
  1982年   20篇
  1981年   25篇
  1980年   33篇
  1979年   3篇
  1978年   10篇
  1977年   132篇
  1976年   259篇
  1975年   9篇
  1973年   1篇
  1965年   1篇
  1964年   1篇
  1954年   1篇
排序方式: 共有3296条查询结果,搜索用时 0 毫秒
91.
92.
We describe laparoscopic diagnosis and treatment for a case of dysgenetic male pseudohermaphroditism with persistent Mullerian ducts. The patient, a 32 year old man, with a history of surgery for hypospadias and cryptorchidism during childhood, was referred because of anejaculation. He was of short stature, with male external genitalia composed of a small penis and hypoplastic testis (1 ml right, 6 ml left side). Plasma follicle stimulating hormone (FSH) was high (17 mUI/ml), testosterone low (1.9 ng/ml), and his karyotype was 46,XY. Pelvic ultrasound, nuclear magnetic resonance (NMR) and genitography disclosed a uterine-like structure with cavity communicating with the urethra. Laparoscopy and urethrocystoscopy confirmed the presence of a 4 cm uterus, which was removed endoscopically at the same time. A biopsy of the left gonad was also performed. The uterus contained endometrial tissue and was fibrotic. Histology of the left gonad showed spermatocytic arrest. We diagnosed dysgenetic male pseudohermaphroditism. Laparoscopy, in our opinion, is an optimal tool to diagnose and treat abnormal sexual conditions.  相似文献   
93.
Morphine inhibits propagating and stimulates nonpropagating colon contractions in monkeys and humans. The use of morphine or other opioids that inhibit propulsive contractions prolongs postoperative ileus. In contrast, ketorolac tromethamine, a nonsteroidal analgesic, has no effect on colon contractions in monkeys. In 14 patients having elective abdominal operations, bipolar electrodes were implanted on the right (n = 13) and left (n = 10) colon. Group A (n = 8) received ketorolac, 30 mg IM q6h, for pain relief. Group B (n = 6) needed supplemental morphine, 2-10 mg IV or IM, plus ketorolac to control their pain. Myoelectric activity was recorded from each subject on postop Days 1-5 and analyzed by computer for electrical control activity (ECA), short and long electrical response activity (ERA), and propagation of long ERA. There was a difference between the two groups in return of propagated long ERA bursts that correlated with clinical recovery from postoperative ileus. Postoperative analgesia with ketorolac resulted in faster resolution of ileus compared to morphine plus ketorolac because opioid-induced motor abnormalities in the colon were avoided.  相似文献   
94.
95.
96.
97.
Well-recognized risk factors for zygomycosis include diabetic ketoacidosis, immunocompromise, and deferoxamine therapy for iron or aluminum overload, usually in patients undergoing kidney dialysis. We report a case of fatal nasal-orbital-cerebral zygomycosis in an 82-year-old man with known myelodysplasia and well-controlled diabetes. He was not receiving deferoxamine. Despite radical surgery and amphotericin B therapy, he died; primary hemochromatosis with gross iron overload was found post mortem. Experimental evidence suggests iron overload without deferoxamine therapy may be a risk factor for zygomycosis; the findings in this case would support this hypothesis.  相似文献   
98.
99.
Sinusitis is commonly reported in patients with AIDS. In addition to the usual bacterial pathogens isolated from immunocompetent patients, sinusitis in patients with AIDS may be caused by a variety of unusual bacteria, viruses, fungi, parasites, and mycobacteria. Histoplasma capsulatum has not typically been associated with sinusitis in either group of patients. We report a case of sinusitis caused by H. capsulatum in a patient with AIDS.  相似文献   
100.
The action of duck egg drop syndrome 1976 (EDS-76) adenovirus on model bilayer lipid membranes (BLM) has been investigated on planar egg phosphatidylcholine membranes and small unilamellar vesicles. It was found that the adenovirus formed channels in planar BLM in a pH-dependent manner. The addition of EDS-76 to planar BLM at pH 5 induced voltage-independent channel activity of about 60 pS conductivity after a lag phase. At pH 3, EDS-76 induced irregular spikes of current across the planar BLM which disappeared after several minutes. The adenovirus also was able to induce pH-dependent leakage of calcein-loaded liposomes. EDS-76 did not induce channel activity in planar BLM or liposome leakage at neutral pH.  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