全文获取类型
收费全文 | 3889篇 |
免费 | 2篇 |
专业分类
化学工业 | 16篇 |
金属工艺 | 1篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
轻工业 | 1篇 |
石油天然气 | 2篇 |
一般工业技术 | 1篇 |
冶金工业 | 3864篇 |
自动化技术 | 4篇 |
出版年
2023年 | 1篇 |
2020年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 7篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 107篇 |
1998年 | 1155篇 |
1997年 | 701篇 |
1996年 | 453篇 |
1995年 | 219篇 |
1994年 | 222篇 |
1993年 | 212篇 |
1992年 | 17篇 |
1991年 | 44篇 |
1990年 | 36篇 |
1989年 | 42篇 |
1988年 | 33篇 |
1987年 | 41篇 |
1986年 | 52篇 |
1985年 | 34篇 |
1984年 | 1篇 |
1983年 | 14篇 |
1982年 | 17篇 |
1981年 | 25篇 |
1980年 | 50篇 |
1979年 | 3篇 |
1978年 | 9篇 |
1977年 | 110篇 |
1976年 | 258篇 |
1975年 | 7篇 |
1964年 | 1篇 |
1955年 | 5篇 |
1954年 | 2篇 |
排序方式: 共有3891条查询结果,搜索用时 15 毫秒
1.
JF Favarel-Garrigues F Sztark ME Petitjean M Thico?pé P Lassié P Dabadie 《Canadian Metallurgical Quarterly》1996,82(2):312-316
Protective immunity against infection with Mycobacterium tuberculosis is imparted by T cells rather than antibodies, but B cells can play a role as antigen-presenting cells and in granuloma formation. We re-evaluated the role of B cells in the course of tuberculous infection in mu-chain knock-out (Ig-) mice. Surprisingly, the organs of M. tuberculosis-infected Ig- mice were found to have three- to eight-fold elevated counts of viable bacilli compared with normal littermates at 3-6 weeks post-infection. Splenic interferon-gamma responses to whole antigen were unimpaired, whilst proliferation to certain mycobacterial peptides was found to be diminished. However, bacille Calmette-Guérin (BCG) vaccination significantly reduced the infection in Ig- mice. The mechanisms by which B cells can influence primary tuberculous infection need further study. 相似文献
2.
SG Rijpkema RG Herbes N Verbeek-De Kruif JF Schellekens 《Canadian Metallurgical Quarterly》1996,117(3):563-566
Epiglottic disruption is an uncommon injury usually associated with significant supraglottic trauma. This injury may be overlooked because of the difficulty in examining the larynx or other associated severe injuries. We present two cases of clinically unsuspected epiglottic disruption that were first seen on MR images of the neck. 相似文献
3.
BS Kendrick BS Chang T Arakawa B Peterson TW Randolph MC Manning JF Carpenter 《Canadian Metallurgical Quarterly》1997,94(22):11917-11922
Understanding the mechanism for sucrose-induced protein stabilization is important in many diverse fields, ranging from biochemistry and environmental physiology to pharmaceutical science. Timasheff and Lee [Lee, J. C. & Timasheff, S. N. (1981) J. Biol. Chem. 256, 7193-7201] have established that thermodynamic stabilization of proteins by sucrose is due to preferential exclusion of the sugar from the protein's surface, which increases protein chemical potential. The current study measures the preferential exclusion of 1 M sucrose from a protein drug, recombinant interleukin 1 receptor antagonist (rhIL-1ra). It is proposed that the degree of preferential exclusion and increase in chemical potential are directly proportional to the protein surface area and that, hence, the system will favor the protein state with the smallest surface area. This mechanism explains the observed sucrose-induced restriction of rhIL-1ra conformational fluctuations, which were studied by hydrogen-deuterium exchange and cysteine reactivity measurements. Furthermore, infrared spectroscopy of rhlL-1ra suggested that a more ordered native conformation is induced by sucrose. Electron paramagnetic resonance spectroscopy demonstrated that in the presence of sucrose, spin-labeled cysteine 116 becomes more buried in the protein's interior and that the hydrodynamic diameter of the protein is reduced. The preferential exclusion of sucrose from the protein and the resulting shift in the equilibrium between protein states toward the most compact conformation account for sucrose-induced effects on rhIL-1ra. 相似文献
4.
5.
6.
G Mangiapan M Vokurka L Schouls J Cadranel D Lecossier J van Embden AJ Hance 《Canadian Metallurgical Quarterly》1996,34(5):1209-1215
The rapid identification of mycobacterial DNA in clinical samples by PCR can be useful in the diagnosis of tuberculous infections, but several large studies have found that the sensitivity of this approach is not better than that of culture. In order to improve the sensitivity of detection of mycobacterial DNA in clinical specimens from patients with paucibacillary forms of tuberculosis, we have developed a procedure permitting the specific capture of mycobacterial DNA in crude samples prior to amplification, thereby concentrating the target sequences and removing irrelevant DNA and other potential inhibitors of the amplification reaction (sequence capture-PCR). By using this approach to capture and amplify two different sequences specific for organisms of the Mycobacterium tuberculosis complex (IS6110 and the direct repeat region), it was possible to detect as little as one genome of mycobacterial DNA in samples containing up to 750 micrograms of total DNA, representing a 10- to 100-fold increase in sensitivity compared with that obtained by purifying total DNA prior to amplification. Detection of the IS6110 sequence in pleural fluid samples from patients with tuberculous pleurisy by sequence capture-PCR gave positive results in 13 of 17 cases, including 3 of 3 culture-positive samples and 10 of 14 culture-negative samples. In contrast, when total DNA was purified from these samples by adsorption to a silica matrix prior to amplification, only the three culture-positive samples were positive by PCR. The sensitivity of detection of the direct repeat sequence in these samples by sequence capture-PCR was similar to that of IS6110 and, in addition, permitted immediate typing of the strains from some patients. We conclude that sequence capture-PCR improves the sensitivity of detection of mycobacterial DNA in paucibacillary samples. This approach should be useful in detecting rare target sequences from organisms implicated in other pathologic processes. 相似文献
7.
Tracheobronchial stent insertion is a relatively new technique used to palliate or cure central airways obstruction. When performed by experienced thoracic endoscopists, this procedure is both safe and effective, even if complications of indwelling stents may require repeat endoscopic intervention. Although proven clinically beneficial to many patients, airway prostheses have not yet been the subject of large comparative case studies or randomized controlled investigations. Reports are often experiential and anecdotal. Further research is needed to determine the effects of stenting on survival in patients with malignant airway disease and its degree of success in patients with benign airway strictures. Only then will airway stents truly deserve their place alongside other therapies for tracheobronchial obstruction. 相似文献
8.
Paroxysmal atrial fibrillation is the most frequent of cardiac arrhythmias and its frequency increases with age. Its diagnosis is difficult since the symptoms are often absent or misleading. It is based on electrocardiogram performed during the attack, and this has been made easier by the Holter technique or by sequential recordings triggered by the patient himself. It is only in special cases, when percritical recordings could not be made that intracavitary electrophysiological study is used to obtain indirect arguments in favour of the diagnosis. All heart diseases can be attended by this cardiac rhythm disorder which usually marks an unfavourable turn in the course of the disease, with an increased risk of sudden death in the end. But in most cases the only disorder found is a common arterial hypertension. Atrial fibrillation carries a risk of peripheral, and in particular cerebral, embolism evaluated at 5% per annum. This risk is high in patients with cardiopathy, but it also exists even with a normal heart. The value of anticoagulants has been demonstrated by large controlled studies, but it is important to know that a very strong anticoagulant treatment is unnecessary to reduce the risk of embolism. Only antiarrhythmic agents can maintain the patients in sinus rhythm for as long as possible before the passage to permanent fibrillation. Although no beneficial effect on mortality has been proved, these drugs are indicated for patients who have very marked symptoms or a major cardiopathy.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
9.
JF DeFrance S Sands FC Schweitzer L Ginsberg JC Sharma 《Canadian Metallurgical Quarterly》1997,9(4):283-293
The purpose of this article is to deliberate the moral and legal dilemma entailed in the weapon of the labour strike as a pressure tactic on the Israeli Finance Ministry regarding job slots, budgets and, in effect, violating the collective agreement signed by the nurses and impairing patients' treatment, as opposed to refraining from striking and suffering the heavy burden of work, the lack of trained personnel, low wages, and the inability to give patients proper, high quality treatment. 相似文献
10.
JF Price 《Canadian Metallurgical Quarterly》1997,27(9):1004-1006
OBJECTIVE: To describe a rare case of right renal agenesia and left pelvic ectopy. To our knowledge, only 10 such cases have been reported in the world literature. METHODS: A 76-year-old male patient who consulted for irritative prostatic syndrome is described. Patient evaluation included IVP and CT. RESULTS: IVP revealed the absence of the right kidney in addition to an anomalous position of the left kidney. The foregoing findings were confirmed by CT. CONCLUSION: This uncommon congenital anomaly is essentially asymptomatic and is generally diagnosed in infants through its complications. In the case described herein, however, this anomaly had been incidentally detected during IVP and CT assessment of a 76-year-old patient who had consulted for irritative prostatic syndrome. 相似文献