全文获取类型
收费全文 | 4523篇 |
免费 | 1篇 |
专业分类
电工技术 | 2篇 |
综合类 | 1篇 |
化学工业 | 17篇 |
建筑科学 | 4篇 |
轻工业 | 3篇 |
无线电 | 5篇 |
一般工业技术 | 4篇 |
冶金工业 | 4475篇 |
自动化技术 | 13篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2014年 | 6篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 3篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2003年 | 9篇 |
2000年 | 2篇 |
1999年 | 127篇 |
1998年 | 1388篇 |
1997年 | 848篇 |
1996年 | 490篇 |
1995年 | 269篇 |
1994年 | 250篇 |
1993年 | 278篇 |
1992年 | 35篇 |
1991年 | 49篇 |
1990年 | 73篇 |
1989年 | 61篇 |
1988年 | 68篇 |
1987年 | 63篇 |
1986年 | 45篇 |
1985年 | 35篇 |
1984年 | 1篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 29篇 |
1980年 | 44篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 93篇 |
1976年 | 204篇 |
1975年 | 5篇 |
1964年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有4524条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
AJ Caraballo 《Canadian Metallurgical Quarterly》1996,30(5):483-484
An outbreak of 154 cases of vampire bat biting in a four-month period in the gold mine of Payapal, a Venezuelan village, is reported. All patients were bitten during the night and the most bites were on their toes. No complication attributed to the bite was reported. Diagnoses of rabies virus made by means of immunofluorescence were negative. A possible reason for this outbreak may been the development of mining areas, with the inhabitants providing an alternative food source for the bats. 相似文献
6.
7.
A procedure is described by which the length of a tendon at the onset of loading is determined objectively. The procedure includes the fitting of third-order polynomial functions on the load-elongation data. The onset of loading is detected by an increasing fit of the polynomial by selective data reduction of the initial part of the load-elongation curve. The procedure results in an objective and reproducible definition of the zero strain level of a tendon. 相似文献
8.
BACKGROUND: While monotherapy has significant limitations in bipolar disorder, few published data addressing alternatives exist. Treatment algorithms have been proposed, but none have undergone empirical evaluation. This study provides a systematic prospective, open evaluation of the effectiveness and tolerability of a treatment algorithm for patients with histories of mania. METHOD: Twenty-eight symptomatic outpatients from a public mental health facility who were diagnosed as having either bipolar I or schizoaffective illness, bipolar type, entered the study. Minimum blood levels of lithium and divalproex sodium were defined. Medications were pushed to predetermined levels (as tolerated) before proceeding to the next algorithm step. Clinical symptoms were assessed monthly using the Brief Psychiatric Rating Scale (BPRS, 27 item) and Clinical Global Impressions scale. RESULTS: Pretreatment and posttreatment clinical symptoms were compared. Over 50% of patients attained 30% improvement from baseline BPRS after 4 months. Thirty-six percent of patients (N = 10) became mood stable, 46% (N = 13) remained mood unstable, and 18% (N = 5) dropped out before completing the algorithm. Although patients who finished the algorithm were taking more medication, either dosage and/or drugs, somatic complaints did not increase. CONCLUSION: The potential benefit of a defined treatment algorithm was demonstrated for these complex and persistently ill patients. Despite long treatment histories, patients improved with more frequent visits and addition of medication(s). A randomized controlled trial comparing a similar treatment algorithm with treatment-as-usual is warranted. 相似文献
9.
Single-unit recordings were made in the intact anesthetized rat of the responses of dorsal horn neurons to C-, Adelta-, and Abeta-fiber stimulation. The postdischarge and windup responses of the same cells along with responses to innocuous stimuli, prod and brush, also were measured. The effects of (-)-bicuculline-methobromide (0.5, 5, 50, and 250 microg) were observed on these neuronal responses. The C- and Adelta-fiber-evoked responses were facilitated significantly in a dose-dependent manner. The input was facilitated, but as the final overall response was not increased by the same factor, windup appeared to be reduced. However, postdischarge, resulting from the increase in the excitability produced by windup, tended to be facilitated. After doses of >/=5 microg bicuculline, stimulation at suprathreshold Abeta-fiber-evoked activity caused enhanced firing, mainly at later latencies corresponding to Adelta-fiber-evoked activity in normal animals. Few cells responded consistently to brush and so no significant change was observed. Responses evoked by innocuous pressure (prod) always were observed in cells that concurrently responded to electrical stimulation with a C-fiber response. This tactile response was facilitated significantly by bicuculline. The effects of N6-cyclopentyladenosine (N6-CPA), an adenosine A1-receptor agonist, was observed after pretreatment with 50 microg bicuculline, as were the effects of morphine and 7-chlorokynurenate (7-CK). N6-CPA inhibited prod, C- and Adelta-fiber-evoked responses as well as the initial and overall final response to the train of C-fiber strength stimuli. Inhibitions were reversed with 8(p-sulphophenyl) theophylline. Morphine, the mu-receptor agonist, also inhibited the postbicuculline responses to prod, C-, and Adelta-fiber responses and initial and final responses to a train of stimuli. Inhibitory effects of morphine were reversed partly by naloxone. 7-CK, an antagonist at the glycine site on the N-methyl-D-aspartate-receptor complex, inhibited the responses to C- and Adelta-fiber-evoked activity as well as prod. The postdischarges were inhibited by this drug. Again both the initial and overall responses of the cell were inhibited. To conclude, bicuculline caused an increase in the responses of deep dorsal horn cells to prod, Adelta-fiber-evoked activity, increased C-fiber input onto these cells along with the appearance of responses at latencies normally associated with Adelta fibers, but evoked by suprathreshold Abeta-fiber stimulation. These alterations may be responsible for some aspects of the clinical phenomenon of allodynia and hyperalgesia. These altered and enhanced responses were modulated by the three separate classes of drugs, the order of effectiveness being 7-CK, N6-CPA, and then morphine. 相似文献
10.