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991.
992.
依据GB/T 15000.3-2008《标准样品工作导则(3)标准样品:定值的一般原则和统计方法》,开展表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)国家标准样品研制工作。以绿茶样品作为研究材料,采用溶剂提取、萃取、高速逆流色谱分离纯化,制备得到EGCG。通过紫外-可见吸收光谱、红外光谱、质谱和核磁共振波谱等方法对EGCG样品进行结构鉴定,并进行均匀性、稳定性检验。采用8 家实验室进行联合定值,并对定值结果进行数据分析。结果:EGCG标准样品均匀性和稳定性良好,定值结果为99.29%,置信度95%的扩展不确定度为0.16%。结论:所制备得到的EGCG样品满足GB/T 15000.3-2008的要求,可用于绿茶相关产品中EGCG的质量控制和方法验证。 相似文献
993.
LE Larsson A Westerlind B Ekstr?m-Jodal NJ Nilsson 《Canadian Metallurgical Quarterly》1993,37(8):761-763
The aim of the present study was to evaluate the use of the vertebral artery for cerebral blood flow studies. In eight dogs a small catheter was introduced into an unligated a. vertebralis sin. Radioactive microspheres (141Cerium) were injected and detected with a gamma camera. The microspheres were distributed to all parts of the brain. The concentrations were highest in the cerebellum, pons and medulla oblongata, while the total activity was greatest in the cerebrum because of its higher weight. The activity in the extracerebral tissues in the head was found to be less than 5% of the brain activity. 相似文献
994.
995.
Knowledge of the appearance and location of the normal fascial structures surrounding the kidneys and the bladder is the key to proper CT analysis of extraperitoneal fluid collections. Recent studies have shown that the renal fascia and the perirenal space are more complex than previously recognized. An extracapsular renal hematoma, confined against the kidney by the posterior renorenal septum within the perirenal space, can entirely simulate a subcapsular hematoma. Pancreatitis fluid can dissect between the discrete layers that constitute the posterior renal fascia, allowing fluid in the anterior pararenal space to extend posterior to the kidney without directly involving the posterior pararenal space. The umbilicovesical fascia separates the small perivesical space from the potential large reservoir of the prevesical space in the extraperitoneal portion of the pelvis. Fluid in the prevesical space can communicate directly with the retroperitoneal spaces surrounding the kidney. In addition to compartmental localization, CT features of the fluid itself or the presence of ancillary findings such as aortic aneurysm, enlarged pancreas, renal mass, or hydronephrosis will frequently indicate the cause and the extent of most extraperitoneal fluid collections. 相似文献
996.
997.
OBJECTIVE: To characterize human autoantigen-antibody systems related to the mitotic poles and spindles. METHODS: Thirty-seven human sera with autoantibodies staining mitotic poles and spindles in indirect immunofluorescence (IIF) studies were further characterized by immunofluorescence on mitotic cells and by immunoblotting and immunoprecipitation. Clinical diagnoses meeting the American College of Rheumatology criteria were based on chart review and interview with the corresponding physicians. RESULTS: Two autoantibody systems reactive with mitotic poles and spindles were defined. Type 1 nuclear mitotic apparatus (NuMA-1) antibodies were identified in the serum of 30 patients. Interphase cells showed a fine, speckled, nuclear staining, while mitotic cells had bright staining of the rim of the centrosomes and light staining of the spindles proximal to the centrosomes. In telophase, the staining shifted from the centrosomes to the reforming nuclei. On immunoblotting, anti-NuMA-1 sera reacted with a 210-kd protein. The reactivity of these sera was identified (with the aid of reference antibodies) as the previously described NuMA antigen-antibody system. Clinical information was available for only 17 of the 30 patients with anti-NuMA-1; of these, 17 (53%) had clinical and lip biopsy findings that met the criteria for Sj?gren's syndrome. NuMA-2 antibodies were found in the sera of 7 patients. Interphase cells showed no nuclear or cytoplasmic staining, but mitotic cells had brightly stained poles and spindles. At anaphase/telophase, staining shifted to the midbody and the intercellular bridge. Anti-NuMA-2 sera immunoprecipitated a protein of 116 kd. This group of patients was more heterogeneous and had both systemic and organ-specific autoimmune diseases. CONCLUSIONS: NuMA protein (here called NuMA-1) and a 116-kd protein (here called NuMA-2) are the major targets of the autoimmune response in the mitotic apparatus, since most of the selected sera (based on IIF staining of the mitotic spindles and poles) recognized 1 of these 2 antigens. 相似文献
998.
999.
DB Miller LE Gray JE Andrews RW Luebke RJ Smialowicz 《Canadian Metallurgical Quarterly》1993,81(3):217-222
Two-dimensional proton nuclear Overhauser effect (NOESY) spectra were obtained as a function of mixing time for two DNA dodecamers, 5'-CGCGAATTCGCG-3' and 5'-CGCAAATTTGCG-3', in aqueous solutions. The time evolution of cross-peak volumes was quantitatively analyzed based on the approximate solution of the relaxation/exchange equation over a range of mixing times from 30 to 150 ms. Inter-proton distances, involving exchangeable protons in key locations of the structures, were calculated and compared to the distances predicted by the crystal structures. These NMR-derived distances enhance the number of constraints, and their accuracy, for determination of solution structures of the two DNA dodecamers. 相似文献
1000.
CR Greenberg CL Taylor JC Haworth LE Seargeant S Philipps B Triggs-Raine BN Chodirker 《Canadian Metallurgical Quarterly》1993,17(1):215-217
Most drugs induce conditioned taste aversions and are therefore commonly supposed to produce nausea or sickness. Paradoxically, some drugs appear to lose induction capability when made to serve as a cue for a second drug that produces more severe sickness, perhaps through selective association with a hypothetical homeostatic or antisickness aftereffect of sickness. Using drug-drug pairings had made antisickness conditioning theory difficult to validate. We report here that rotation serves in lieu of a drug cue in rats. Rotation-drug pairings eliminate drug interactions and enable the sorts of parametric manipulations required to validate the theory. By postulating a common sickness mechanism to explain both taste aversion and aversion failure, the theory places the phenomenon within an adaptive evolutionary framework. Successful application could yield a direct countermeasure to severe nausea in clinical settings. 相似文献