全文获取类型
收费全文 | 2425篇 |
免费 | 0篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 32篇 |
建筑科学 | 1篇 |
轻工业 | 1篇 |
石油天然气 | 2篇 |
无线电 | 5篇 |
一般工业技术 | 4篇 |
冶金工业 | 2376篇 |
自动化技术 | 2篇 |
出版年
2021年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 79篇 |
1998年 | 695篇 |
1997年 | 405篇 |
1996年 | 248篇 |
1995年 | 143篇 |
1994年 | 146篇 |
1993年 | 152篇 |
1992年 | 34篇 |
1991年 | 36篇 |
1990年 | 40篇 |
1989年 | 67篇 |
1988年 | 40篇 |
1987年 | 36篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1983年 | 4篇 |
1982年 | 11篇 |
1981年 | 16篇 |
1980年 | 18篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 54篇 |
1976年 | 113篇 |
1975年 | 1篇 |
1955年 | 2篇 |
排序方式: 共有2425条查询结果,搜索用时 0 毫秒
991.
Sixty ankle arthroscopies were performed on patients with chronic soft-tissue impingement of the ankle after an ankle sprain between January 1989 and January 1994. Preoperative examination findings featured tenderness localized to the anterolateral aspect of the ankle, no instability, and, with the exception of 2 patients, normal radiographs. A preoperative bone scan was performed on 34 patients and was positive in each case but was not specific. Arthroscopy was performed an average of 23 months after injury. Results were determined by using a new ankle rating score. Hypertrophic synovium, synovitis, or fibrous adhesions were arthroscopically visualized and resected in all cases. The average follow-up was 27 months (range, 6 to 64 months). Thirty-one patients underwent complete evaluation and 29 were evaluated over the telephone. There were 51 excellent, 7 good, 1 fair, and 1 poor results. The diagnosis of chronic soft-tissue impingement of the ankle can be made from an appropriate history, thorough physical examination, and plain radiographs. Ankle arthroscopy with resection of impinging hypertrophic synovium or fibrous bands occurring after an ankle sprain was effective in alleviating pain in athletes. 相似文献
992.
993.
CD Adair L Sanchez-Ramos D Whitaker DC McDyer L Farah D Briones 《Canadian Metallurgical Quarterly》1996,174(3):966-970
OBJECTIVE: Our purpose was to determine the efficacy and safety of a trial of labor in patients previously delivered at least once by a lower uterine vertical cesarean section. STUDY DESIGN: A retrospective review was performed at a single tertiary perinatal center, The University of Florida Health Science Center, Jacksonville. The medical records of all patients with a previous low vertical cesarean section who underwent a trial of labor during a 72-month period from January 1988 until December 1993 were reviewed. The medical records of the next two patients who did not have a prior uterine incision admitted to labor and delivery after the index case served as the controls. The duration and outcome of labor, including mode of delivery, maternal and perinatal morbidity, and birth trauma were evaluated. RESULTS: Of 77 patients with a previous low vertical cesarean incision, 11 (14.3%) had a repeat operation compared with 14 of 154 patients (9.0%) in the no previous cesarean section group (not significant). No differences were noted in the incidences of operative vaginal deliveries or prolonged duration of the first or second stages of labor, or in the rate or maximum dose of oxytocin infusion between the two groups. One patient in the previous cesarean section group had uterine rupture. The incidence of umbilical artery pH < or = 7.20 was similar. No difference in the number of infants with 1- or 5-minute Apgar scores < or = 7 was noted. CONCLUSION: A trial of labor in women with previous low vertical cesarean sections results in an acceptable rate of vaginal delivery and appears safe for both mother and fetus. 相似文献
994.
995.
DC Rice 《Canadian Metallurgical Quarterly》1996,18(3):229-32; discussion 271-6
996.
HJ Broxterman P Sonneveld N Feller GJ Ossenkoppele DC W?hrer CA Eekman M Schoester J Lankelma HM Pinedo B L?wenberg GJ Schuurhuis 《Canadian Metallurgical Quarterly》1996,87(11):4809-4816
We have compared multiple assays for the P-glycoprotein (Pgp/MDR1) phenotype in fresh and thawed adult acute leukemia to validate and quantitate measures for the expression and function of Pgp. The results are related to the Pgp-expressing KB8 and KB8-5 call lines. The most sensitive assay was the measurement of modulation of the rhodamine 123 (R123) fluorescence by 2 micromol/L PSC833, followed by the modulation of the probe calcein-AM. We also found a good intralaboratory and interlaboratory correlation between the values of the R123/PSC833 assay for fresh as well as thawed samples. In addition, the affects of PSC833 on 3H-daunorubicin (DNR) accumulation, DNR fluorescence, and 3H-vincristine accumulation were very similar. The correlation between the DNR/PSC833 and R123/PSC833 test was r = .86 (N = 51). The modulation of drug accumulation by 8 micromol/L verapamil was the some as the PSC833 effect for DNR (117%, N = 21), but was higher for vincristine in every single case (161% v 121%, N = 22; P< .001), indicating additional verapamil effects, not related to Pgp. The correlation of the staining of viable cells for Pgp with the monoclonal antibody MRK16 was r = .77 (N = 52) for the R123/PSC833 functional test and r = .84 (N = 50) for the DNR/PSC833 test. From these results it could be calculated that a maximal increase of the mean DNR accumulation of about 50% can be achieved by blocking Pgp pump activity with PSC833 in leukemic blast samples with the highest mean Pgp expression. Subpopulations of blast calls with higher Pgp activity are likely to be present. Their relevance has to be studied further. The methods outlined here allow the reliable, quantitative monitoring of the Pgp/MDR1 phenotype in leukemias in multicentered, clinical Pgp modulation studies. 相似文献
997.
998.
999.
1000.