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   1338篇
  免费   2篇
  国内免费   2篇
化学工业   7篇
金属工艺   1篇
机械仪表   1篇
建筑科学   1篇
矿业工程   1篇
轻工业   9篇
石油天然气   1篇
无线电   3篇
一般工业技术   3篇
冶金工业   1313篇
自动化技术   2篇
  2020年   1篇
  2019年   3篇
  2018年   2篇
  2017年   1篇
  2015年   2篇
  2013年   1篇
  2012年   2篇
  2007年   1篇
  2005年   1篇
  2004年   2篇
  2003年   3篇
  1999年   37篇
  1998年   391篇
  1997年   241篇
  1996年   145篇
  1995年   80篇
  1994年   63篇
  1993年   78篇
  1992年   9篇
  1991年   16篇
  1990年   8篇
  1989年   13篇
  1988年   18篇
  1987年   15篇
  1986年   13篇
  1985年   11篇
  1984年   1篇
  1983年   4篇
  1982年   8篇
  1981年   16篇
  1980年   16篇
  1979年   1篇
  1978年   4篇
  1977年   48篇
  1976年   80篇
  1975年   4篇
  1955年   3篇
排序方式: 共有1342条查询结果,搜索用时 31 毫秒
51.
52.
OBJECTIVE: To assess the outcomes of changes in mental health policy introduced in Italy in 1978. METHODS: Data on psychiatric services, before and after the policy change, are presented. Effects of change are evaluated through indicators related to four issues: transfer of care, criminalisation of the mentally ill, suicides, and homelessness. RESULTS: Admissions of new patients to mental hospitals have been stopped and the size of the mental hospital population is now very low (26 per 100,000 population). Psychiatric care has been shifted to community services including general hospital psychiatric units. There has been an overall reduction of psychiatric hospitalisation. However, the provision of residential facilities is inadequate and community services are unevenly distributed across the country. Few negative effects of changing patterns of care have been reported, although the low quality of data limits the validity of such a conclusion. Outcome of care in areas where the full range of community services is available has been rated as satisfactory. CONCLUSIONS: Although care of the mentally ill has been shifted to community services, we lack hard data on the social and clinical outcome of community care at the nation-wide level. Long-term monitoring and evaluation of community services is a high priority in Italy.  相似文献   
53.
54.
55.
56.
Two noninvasive tests for assessing pancreatic exocrine function, the cholesteryl-[14C]octanoate breath test and the HPLCN-benzoyl-tyrosyl-p-aminobenzoic acid/p-aminosalicylic acid (NBT-PABA/PAS) test, were simultaneously performed in nine patients with pancreatic exocrine insufficiency due to chronic pancreatitis and in nine healthy volunteers. 14CO2 output in breath and plasma PABA concentration rose slowly in patients but increased rapidly in healthy subjects. The measurement time giving the best discrimination between both groups was 120 min for the cholesteryl-[14C]octanoate breath test and 90 min for the plasma PABA test. At these points, both single-sample tests had essentially identical diagnostic sensitivity. The diagnostic sensitivities of the two single-sample tests were equal to that of the cumulative 6-h urinary PABA recovery and the cumulative 6-h urinary PABA/PAS ratio. We conclude that, for both the cholesteryl-[14C]octanoate breath test and the plasma PABA test, a single test sample is sufficient for rapid detection of impaired exocrine pancreatic function.  相似文献   
57.
The effect of two different methods of reconstruction of flatfoot deformity and the role of the posterior tibial tendon on the contact characteristics of the hindfoot joints were quantified using pressure-sensitive film. Each of 10 cadaver feet was loaded quasi-statically by an axial compressive force to simulate varying loads. First, a specimen was tested intact, then it was tested after sectioning the spring ligament and loading the specimen cyclically to create one type of flatfoot deformity. It was then tested again after reconstructing the deformity. Reconstructions used were the Dillwyn-Evans procedure (bone graft in osteotomy of the calcaneus) or the calcaneocuboid distraction arthrodesis (CCDA). We found that surgically produced flatfoot deformity altered mainly the talonavicular joint, by decreasing its contact area. The Dillwyn-Evans method had less effect on the talonavicular joint (altering 2 of 6 measured parameters) than the CCDA (3 of 6) and more effect on the anteriomedial facet (altering 3 of 6 parameters) than the CCDA (1 of 6). The Dillwyn-Evans method had more effect on the posterior facet (altering 2 of 6 measured parameters) than the CCDA (1 of 6). Function of the posterior tibial tendon had no effect on contact characteristics of the hindfoot joints after either type of reconstruction. These findings are based on measurements using a quasi-statically-loaded foot model at three selected positions, and results may be different with dynamic loading.  相似文献   
58.
59.
PURPOSE: We describe a protocol designed to evaluate the use of twice daily radiation used together with cisplatin and 5 fluorouracil (5-FU) in the treatment of operable transitional cell carcinoma of the bladder with potential bladder preservation. MATERIALS AND METHODS: A total of 18 consecutive patients with T2-T4a bladder tumors underwent as complete a transurethral resection as possible, which was visibly complete in 14 cases. They then received twice daily radiation and infusion cisplatin and 5-FU during an induction phase. No therapy was given for 3 weeks, following which patients were reevaluated cystoscopically. Cases of clinical complete response by biopsy and cytology were consolidated with further chemotherapy/radiation using the same chemotherapeutic agents and radiation schedule. Patients who had incomplete responses were advised to undergo an immediate radical cystectomy. Of the 18 patients 15 subsequently received 3 cycles of adjuvant chemotherapy, consisting of methotrexate, cisplatin and vinblastine. Median followup for the entire group is 32 months. RESULTS: Of the 18 patients 14 had no detectable tumor after induction therapy. Of the 4 patients with persistent tumor 2 underwent radical cystectomy and 2 refused cystectomy, 1 of whom was treated with partial cystectomy and the other with consolidation chemotherapy/radiation. The actuarial overall survival at 3 years was 83%. The chance of a patient being alive at 3 years with a native bladder was 78%. No patient required cystectomy for hematuria or bladder shrinkage. Three patients in whom superficial tumors developed were treated successfully with bacillus Calmette-Guerin. Small bowel obstruction in 1 case was corrected surgically. CONCLUSIONS: This pilot study demonstrates a high rate of response to this combined chemotherapy/radiation regimen in conjunction with a visibly complete transurethral resection. Reevaluation after a short induction phase allows for the early selection of patients with persistent disease for radical cystectomy.  相似文献   
60.
A total of 88 Fallopian tubes from 44 patients was examined with hysterosalpingo contrast sonography (HyCoSy), hysterosalpingogram (HSG), and laparoscopic chromopertubation (LC) in order to assess their relative accuracy for measuring tubal patency. HyCoSy was done by transvaginal ultrasound and the contrast was SH U 454 (Echovist). The flow of multiple fractions of the contrast medium through each Fallopian tube was observed in real time in appropriate imaging planes by means of a transvaginal probe. Compared with laparoscopic results, we found a sensitivity of 85.2%, a specificity of 85.2%, a positive predictive value (PPV) of 71.9%, a negative predictive value (NPV) of 92.9% and concordance (HyCoSy/LC) of 85.2%, while the corresponding values for HSG were sensitivity = 85.2%, specificity = 83.6%, PPV = 69.7%, NPV = 92.7% and concordance (HSG/LC) of 84.1%. Compared with HSG results, HyCoSy obtained a co-positivity of 66.7%, a co-negativity of 81.8% and a concordance of 76.1%. In conclusion, HyCoSy with SH U 454 proved to be a reliable and safe modality for evaluating tubal patency; it is suitable as an outpatient diagnostic procedure to be used before more invasive procedures.  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