全文获取类型
收费全文 | 2329篇 |
免费 | 1篇 |
专业分类
化学工业 | 22篇 |
机械仪表 | 2篇 |
建筑科学 | 2篇 |
轻工业 | 12篇 |
石油天然气 | 1篇 |
一般工业技术 | 9篇 |
冶金工业 | 2274篇 |
自动化技术 | 8篇 |
出版年
2022年 | 2篇 |
2019年 | 2篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 1篇 |
2003年 | 4篇 |
2002年 | 1篇 |
1999年 | 54篇 |
1998年 | 699篇 |
1997年 | 388篇 |
1996年 | 269篇 |
1995年 | 138篇 |
1994年 | 130篇 |
1993年 | 121篇 |
1992年 | 17篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 41篇 |
1988年 | 36篇 |
1987年 | 22篇 |
1986年 | 25篇 |
1985年 | 29篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 19篇 |
1980年 | 23篇 |
1978年 | 6篇 |
1977年 | 66篇 |
1976年 | 140篇 |
1975年 | 6篇 |
1965年 | 1篇 |
排序方式: 共有2330条查询结果,搜索用时 15 毫秒
91.
92.
The induction of Fas ligand (FasL) mRNA expression and FasL-mediated cytotoxicity in CD8+ CTL is a rapid and transient response to activation via the TCR. This response can also be initiated by pharmacologic activation of two major TCR signaling pathways using phorbol ester (PMA) and calcium ionophore (ionomycin). In these experiments using CD8+ alloreactive cell lines, we demonstrate that induction of FasL mRNA can occur in response to either PMA or ionomycin independently. However, only the ionomycin pathway is sensitive to inhibition by cyclosporine A. Both pathways are blocked by genistein, a general protein tyrosine kinase inhibitor. The magnitude of induction of FasL mRNA is not proportional to the manifested FasL-dependent cytotoxicity. We also found a calcium requirement for cytotoxicity that is unrelated to FasL mRNA induction. In addition to the positive effects of constitutive and induced calcium levels on FasL-mediated cytotoxicity, calcium may play a role in the rapid down-regulation of the response. We also present data suggesting that CD2 and LFA-1 contribute to FasL-mediated cytotoxicity. Together these results suggest pathways by which partial TCR activation could, among the many activation-induced functions of a T cell, selectively lead to the induction of FasL-mediated cytotoxicity that can be regulated by lineage/ activation-dependent accessory molecules on the target. 相似文献
93.
Hypocomplementemic urticarial vasculitis (HUV) is often misdiagnosed. The response to drug therapy may be unsatisfactory, and immunosuppressive therapy may be associated with significant side effects. A 35-year-old patient whose condition was resistant to cyclophosphamide, corticosteroids, pentoxyphylline, cyproheptadine, sulindac, and colchicine was maintained in remission with dapsone, which may be the drug of choice for HUV. Emphysema has been reported to complicate HUV, but this is the first account of vasculitis-related emphysema with no confounding history of tobacco smoke exposure. The relationship of proteolytic injury to the pulmonary and other manifestations is considered, as is the possible role for dapsone in reducing it. 相似文献
94.
Affinity matured murine monoclonal antibody producing cell lines can now be rapidly generated using a novel repetitive, multiple site immunization strategy designated RIMMS. RIMMS capitalizes on rapid hypermutation and affinity maturation events which occur in B cell populations localized within secondary lymphatic tissue early in response to antigenic challenges. A murine myeloma cell line, P3XBcl-2-13, stably transfected with Bcl-2, enhances the outgrowth of hybridomas following somatic fusion with immune lymphocytes isolated from pooled peripheral lymph nodes (PLN) 8-14 days after the initial immunization. Immunizations somatic fusion, screening and isolation of affinity matured IgG secreting monoclonal antibody cell lines occur within a one month time period. By using RIMMS, we have been able to expedite the isolation of affinity matured monoclonal antibodies to numerous antigens, including a drug hapten. 相似文献
95.
96.
Phalloidin was shown to increase the ATPase activity and Ca2+ sensitivity of both bovine cardiac and rabbit psoas myofibrils when assayed in a solution containing 50 mM KCl, 100 mM MOPS (pH 7.0), 2 mM MgCl2, 1 mM ATP, 2 mM EGTA, and varying concentrations of Ca2+ (temperature 21-22 degrees C). The phalloidin effect in cardiac myofibrils developed over a time course of several minutes in the presence of 50 microM phalloidin. Relative increase of ATPase activity was maximal at pCa 8 and decreased with decrease in pCa. In cardiac myofibrils the increase was about 70% at pCa 8 and 20% at pCa 4 following 20-30 min pre-incubation with 2 microM or 50 microM phalloidin. The effect persisted after excess phalloidin was washed out. The increase in Ca2+ sensitivity was approximately 0.15 pCa units. For skeletal myofibrils treated with 2 microM phalloidin all changes were considerably less than those seen with cardiac myofibrils and the changes were even less when the myofibrils were exposed to 50 microM phalloidin. These results show that when specifically bound to actin, phalloidin can change the kinetic parameters of the cross-bridge cycle and may also alter the Ca2+ sensitivity of the contractile system. The effects of phalloidin seem to vary with muscle type. 相似文献
97.
98.
AR Butler BC Gilbert P Hulme LR Irvine L Renton AC Whitwood 《Canadian Metallurgical Quarterly》1998,28(5):471-476
The role of pharmacies that specialize in the treatment of specific chronic diseases in the alternate-site health care setting is discussed. The optimal use of medications through disease management programs can improve patient outcomes and lower overall health care costs. The increase in disease management programs has spawned the growth of disease-specific pharmacies in the home care and other alternate-site health care settings. These pharmacies usually operate from a single location or are regionalized operations that deliver pharmaceutical products to patients throughout the United States. The pharmacies employ clinicians who specialize in a particular disease. These clinicians conduct comprehensive patient education programs, drug-use review, and compliance monitoring. Disease management pharmacies focus on chronic, expensive diseases; costs related to inventory, equipment, and storage can be very high. Many disease management pharmacies are involved in preferred-distribution or closed-distribution arrangements with pharmaceutical manufacturers. Pharmacists involved in disease management programs routinely send compliance information about their patients to pharmaceutical companies, managed care organizations, or prescribing physicians. Disease management pharmacies act as advocates for patients with particular chronic diseases. Various foundations and patient advocacy and research groups have created their own disease management pharmacies. Disease management has also reached the community pharmacy practice setting. Pharmacies specializing in the treatment of specific chronic diseases in the alternate-site health care setting can improve health care and promote efficient use of health care dollars. 相似文献
99.
100.