全文获取类型
收费全文 | 831篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
化学工业 | 1篇 |
机械仪表 | 1篇 |
一般工业技术 | 2篇 |
冶金工业 | 825篇 |
原子能技术 | 1篇 |
自动化技术 | 2篇 |
出版年
2020年 | 1篇 |
2004年 | 1篇 |
1999年 | 29篇 |
1998年 | 238篇 |
1997年 | 154篇 |
1996年 | 93篇 |
1995年 | 65篇 |
1994年 | 50篇 |
1993年 | 43篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 8篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 14篇 |
1985年 | 7篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1978年 | 1篇 |
1977年 | 18篇 |
1976年 | 48篇 |
排序方式: 共有832条查询结果,搜索用时 31 毫秒
61.
TG McInerney 《Canadian Metallurgical Quarterly》1993,57(4):871-3, 876-82, 887-90
62.
We performed pretreatment brain MRIs in 25 patients with neurologically symptomatic Wilson's disease (WD) and clinical and MRI follow-up in 16 of them. All 25 pretreatment MRIs revealed abnormalities, with abnormal high-signal intensity (HSI) in bilateral thalami being the most common (92%). HSI lesions in the brainstem (84%) and the basal ganglia (72%) were also common. Brain atrophy was present in 88% of the 25 patients. In the follow-up period of 5 to 24 months, during which the patients were treated with D-penicillamine, both HSI lesions and neurologic symptoms improved in 88% of the 16 patients, but the brain atrophy did not change. 相似文献
63.
OBJECTIVE: The patient who voices suicidal intent in terms of the future or in terms of certain life contingencies presents special difficulties for the therapist. The authors outline the challenges posed by this problem for assessment, clinical management, and risk management. METHOD: The authors examined and analyzed case examples from both clinical and risk-management aspects. RESULTS: Problematic cases can be grouped into categories that offer insight as to management. The authors discuss this area and offer suggestions for appropriate clinical responses to this challenge. CONCLUSIONS: The authors recommend that therapists 1) treat the expressed "date with death" as a communication to be explored, 2) explore the problem of helplessness while monitoring their own countertransference responses, 3) assess the patient's competence to inform clinicians about suicidal state, and 4) readily use involuntary commitment. 相似文献
64.
KI Arnautovi? O al-Mefty TG Pait AF Krisht MM Husain 《Canadian Metallurgical Quarterly》1997,86(2):252-262
The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures. Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope. This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous-cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the "suboccipital cavernous sinus." Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed. 相似文献
65.
JE Boyson KK Iwanaga JA Urvater AL Hughes TG Golos DI Watkins 《Canadian Metallurgical Quarterly》1999,49(2):86-98
HLA-G is a nonclassical major histocompatibility complex (MHC) class I molecule that is expressed only in the human placenta, suggesting that it plays an important role at the fetal-maternal interface. In rhesus monkeys, which have similar placentation to humans, the HLA-G orthologue is a pseudogene. However, rhesus monkeys express a novel placental MHC class I molecule, Mamu-AG, which has HLA-G-like characteristics. Phylogenetic analysis of AG alleles in two Old World primate species, the baboon and the rhesus macaque, revealed limited diversity characteristic of a nonclassical MHC class I locus. Gene trees constructed using classical and nonclassical primate MHC class I alleles demonstrated that the AG locus was most closely related to the classical A locus. Interestingly, gene tree analyses suggested that the AG alleles were most closely related to a subset of A alleles which are the products of an ancestral interlocus recombination event between the A and B loci. Calculation of the rates of synonymous and nonsynonymous substitution at the AG locus revealed that positive selection was not acting on the codons encoding the peptide binding region. In exon 4, however, the rate of nonsynonymous substitution was significantly lower than the rate of synonymous substitution, suggesting that negative selection was acting on these codons. 相似文献
66.
RL Summitt TG Stovall GH Lipscomb SA Washburn FW Ling 《Canadian Metallurgical Quarterly》1994,171(6):1480-4; discussion 1484-7
OBJECTIVE: This study examines our continuing experience in performing vaginal hysterectomies and laparoscopy-assisted vaginal hysterectomies with an outpatient protocol. The purpose was to review factors associated with discharge and hospitalization. STUDY DESIGN: Surgical records from all women entering our previously reported outpatient hysterectomy protocol were reviewed. Demographics, surgical indications, intraoperative data, and postoperative data were studied, and their associations with patient discharge and hospitalization were determined. Specific attention was directed to complications. RESULTS: The study group consisted of 133 women. Twelve women (9.0%) were not discharged from the hospital and 5 (3.8%) required readmission. Surgical indications, the type of hysterectomy, and the requirement for pain medication revealed no association with hospitalization. The occurrence of an intraoperative complication (p < 0.000), the need for transfusion (p = 0.043), and postoperative antiemetics (p = 0.013) were statistically associated with hospitalization. In addition, low hematocrit values and elevated temperatures on the first and second postoperative days were associated with hospitalization. CONCLUSION: Long-term experience with outpatient hysterectomy reveals a hospitalization rate of 12.8%. Complications, blood loss, elevated temperatures, and postoperative nausea are the major determinants of patient discharge and hospitalization. Readmission rates continue to remain low. 相似文献
67.
Displacement of phenytoin (90% bound to albumin) by other highly albumin-bound drugs like salicylate has been well documented. Other widely used nonsteroidal antiinflammatory drugs like tolmetin, ibuprofen, and naproxen are also strongly bound to albumin and can potentially displace phenytoin. However, phenytoin-ibuprofen interaction has been poorly studied in the past, and interaction of phenytoin with tolmetin or naproxen has not been studied before. For normal serum pool (albumin 3.7 g/dl), we observed significant increases in free phenytoin concentrations only with antiinflammatory drug concentrations at the upper end of therapeutic or above therapeutic concentrations. However, for the uremic pool (albumin 2.9 g/dl), displacement of phenytoin was significant even at the lower end of therapeutic concentrations of those antiinflammatory drugs. Of the three antiinflammatory drugs we studied, ibuprofen caused the highest displacement of phenytoin. 相似文献
68.
RE Schrohenloher WJ Koopman TG Woodworth LW Moreland 《Canadian Metallurgical Quarterly》1996,23(11):1845-1848
OBJECTIVE: To investigate the effect of diphtheria toxin interleukin 2 recombinant fusion protein (DAB 486IL-2) on in vitro synthesis of immunoglobulin and rheumatoid factor (RF) in patients with severe refractory rheumatoid arthritis (RA) enrolled in a phase II, double blind, placebo controlled study. METHODS: Anticoagulated venous blood samples were obtained before (Day 1) and after (Day 28) intravenous infusion of either DAB 486IL-2 at 0.075 mg/kg/day (12 patients) or saline placebo (10 patients) on Days 1-5. Peripheral blood leukocytes (PBL) were prepared by density gradient centrifugation, cultured in the presence and absence of pokeweed mitogen (PWM) for one week, and culture supernatants assayed for immunoglobulins and IgM RF by ELISA. RESULTS: Compared to placebo treated patients, PWM induced IgM RF synthesis by PBL decreased after treatment with DAB 486IL-2 (p = 0.043). However, there was no apparent correlation with clinical improvement. PWM induced IgM, IgA, and IgG synthesis also tended to decrease, although the changes did not attain statistical significance. In contrast, PWM induced IgM RF, IgM, IgA, and IgG synthesis by PBL from patients treated with placebo tended to increase during the observation period. Spontaneous immunoglobulin and IgM RF production by PBL from either the DAB 486IL-2 or placebo patients remained stable. CONCLUSION: These observations raise the possibility that DAB 486IL-2 may diminish B cell function either directly or indirectly through effects on T cell function, but the change may not correspond to clinical response. 相似文献
69.
JC Mohle-Boetani JE Koehler TG Berger PE LeBoit CA Kemper AL Reingold BD Plikaytis JD Wenger JW Tappero 《Canadian Metallurgical Quarterly》1996,22(5):794-800
Clinical characteristics associated with bacillary angiomatosis and bacillary peliosis (BAP) in patients with human immunodeficiency virus (HIV) infection were evaluated in a case-control study; 42 case-patients and 84 controls were matched by clinical care institution. Case-patients presented with fever (temperature, > 37.8 degrees C; 93%), a median CD4 lymphocyte count of 21/mm3, cutaneous or subcutaneous vascular lesions (55%), lymphadenopathy (21%), and/or abdominal symptoms (24%). Many case-patients experienced long delays between medical evaluation and diagnosis of BAP (median, 4 weeks; range, 1 day to 24 months). Case-patients were more likely than controls to have fever, lymphadenopathy, hepatomegaly, splenomegaly, a low CD4 lymphocyte count, anemia, or an elevated serum level of alkaline phosphatase (AP) (P < .001). In multivariate analysis, a CD4 lymphocyte count of < 200/mm3 (matched odds ratio [OR], 9.9; P < .09), anemia reflected by a hematocrit value of < 0.36 (OR, 19.7; P < .04), and an elevated AP level of > or = 2.6 mukat/L (OR, 23.9; P < .05) remained associated with disease after therapy with zidovudine was controlled for. BAP should be considered an AIDS-defining opportunistic infection and should be included in the differential diagnosis for febrile, HIV-infected patients with cutaneous or osteolytic lesions, lymphadenopathy, abdominal symptoms, anemia, or an elevated serum level of AP. 相似文献
70.
SL Aldrich LL Berger DJ Kesler TG Nash RH McCusker 《Canadian Metallurgical Quarterly》1996,74(2):420-428
A 2 x 3 factorial arrangement of treatments was used to elucidate the mechanism(s) by which prenatal androgenization improves postnatal rate and efficiency of growth and composition of gain in beef heifers. Fifteen control (C) and 15 prenatally androgenized (PA) Angus x Simmental heifers (prenatal treatment, Pretrt) received no (N), estrogen (E), or estrogen and testosterone (ET) implants postnatally (postnatal treatment, Posttrt) to evaluate whether the postpubertal growth response after prenatal androgenization could be induced in prepubertal heifers. Blood was collected from the heifers at 6 +/- 1, 9 +/- 1, and 12 +/- 1 mo of age and analyzed from serum concentrations of growth hormone (GH), IGF-I, IGF-II, insulin, thyroxine (T4), and triiodothyronine (T3). Season of the year had a greater effect on hormone concentrations than either Pretrt or Posttrt, and there were no Pretrt x Posttrt interactions. Prenatal treatment, PA, had no effect on GH; however, Posttrt E and ET increased (P < .001) GH concentrations. Prenatal treatment, PA, increased (P < .05) IGF-I concentrations, and there was a nonsignificant increase (P = .11) in IGF-I concentrations with Posttrt E and ET. Concentrations of IGF-II were unaffected by Pretrt PA; however, they were lower (P < .01) in the Posttrt E and ET groups. Insulin, T4, T3, BW, and ADG were not affected by Pretrt and Posttrt. Concentrations of GH and IGF-I were increased in heifers that received Pretrt PA and(or) Posttrt E and ET in a manner to support improved growth performance; however, BW and ADG were similar. In prepubertal beef heifers, factors in addition to increased GH and IGF-I seem to be necessary for improved growth performance. 相似文献