首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3772篇
  免费   31篇
电工技术   39篇
综合类   2篇
化学工业   190篇
金属工艺   29篇
机械仪表   49篇
建筑科学   104篇
矿业工程   5篇
能源动力   45篇
轻工业   150篇
水利工程   32篇
石油天然气   10篇
无线电   153篇
一般工业技术   270篇
冶金工业   2443篇
原子能技术   23篇
自动化技术   259篇
  2021年   18篇
  2020年   13篇
  2019年   16篇
  2018年   17篇
  2017年   17篇
  2016年   17篇
  2015年   21篇
  2014年   37篇
  2013年   119篇
  2012年   43篇
  2011年   64篇
  2010年   44篇
  2009年   42篇
  2008年   53篇
  2007年   71篇
  2006年   66篇
  2005年   62篇
  2004年   57篇
  2003年   44篇
  2002年   62篇
  2001年   37篇
  2000年   38篇
  1999年   98篇
  1998年   673篇
  1997年   406篇
  1996年   295篇
  1995年   169篇
  1994年   157篇
  1993年   150篇
  1992年   54篇
  1991年   58篇
  1990年   54篇
  1989年   60篇
  1988年   59篇
  1987年   46篇
  1986年   45篇
  1985年   55篇
  1984年   16篇
  1983年   25篇
  1982年   35篇
  1981年   38篇
  1980年   29篇
  1979年   15篇
  1978年   18篇
  1977年   69篇
  1976年   121篇
  1975年   13篇
  1973年   15篇
  1972年   14篇
  1971年   9篇
排序方式: 共有3803条查询结果,搜索用时 46 毫秒
1.
The diagnosis and treatment of prostate cancer (PCa) is a major health-care concern worldwide. This cancer can manifest itself in many distinct forms and the transition from clinically indolent PCa to the more invasive aggressive form remains poorly understood. It is now universally accepted that glycan expression patterns change with the cellular modifications that accompany the onset of tumorigenesis. The aim of this study was to investigate if differential glycosylation patterns could distinguish between indolent, significant, and aggressive PCa. Whole serum N-glycan profiling was carried out on 117 prostate cancer patients’ serum using our automated, high-throughput analysis platform for glycan-profiling which utilizes ultra-performance liquid chromatography (UPLC) to obtain high resolution separation of N-linked glycans released from the serum glycoproteins. We observed increases in hybrid, oligomannose, and biantennary digalactosylated monosialylated glycans (M5A1G1S1, M8, and A2G2S1), bisecting glycans (A2B, A2(6)BG1) and monoantennary glycans (A1), and decreases in triantennary trigalactosylated trisialylated glycans with and without core fucose (A3G3S3 and FA3G3S3) with PCa progression from indolent through significant and aggressive disease. These changes give us an insight into the disease pathogenesis and identify potential biomarkers for monitoring the PCa progression, however these need further confirmation studies.  相似文献   
2.
3.
PURPOSE: We designed a phase I-II trial of three active agents, paclitaxel, ifosfamide, and vinorelbine, in advanced non-small-cell lung cancer (NSCLC) to: 1) define the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of paclitaxel with filgrastim (G-CSF) support; and 2) determine the overall response rate and median survival of patients treated on this regimen. PATIENTS AND METHODS: We treated cohorts of patients with stage IIIB or IV NSCLC with ifosfamide 1.2-1.6 g/m2/day x 3 and vinorelbine 20-25 mg/m2/day x 3 and escalating doses of paclitaxel at 100-175 mg/m2 on day 2 with G-CSF support on a 21-day cycle. One prior experimental single-agent chemotherapy regimen was allowed. RESULTS: Fifty-six patients, were enrolled on this trial: 27 on the phase I portion of the study and an additional 29 at the recommended phase II dose (RPTD). Thirteen patients had received prior chemotherapy. Paclitaxel doses of 175 mg/m2 and 150 mg/m2 produced dose-limiting myelosuppression, and the RPTD was determined to be paclitaxel 135 mg/m2 with ifosfamide 1.2 g/m2/day on days 1-3 and vinorelbine 20 mg/m2/ day on days 1-3 with G-CSF support. The overall response rate was 18%, with a median survival of 6.1 months. Six of 35 patients (17%) treated at the RPTD achieved a partial response to therapy. Grade IV neutropenia was observed in 19 of 35 patients at this dose, with eight patients suffering febrile neutropenia. CONCLUSIONS: This non-cisplatin-containing three-drug regimen has substantial toxicity and low activity in advanced NSCLC, and does not seem to improve on prior regimens. It is unclear whether the lack of efficacy relates to an antagonistic reaction between the specific drugs, administration schedule, or to subtherapeutic doses of the individual agents.  相似文献   
4.
14 medicated hypertensive, 15 nonmedicated mild hypertensive, 39 normotensive, and 13 hypotensive adults participated in a 1–2 hr laboratory experiment that assessed each S's symptoms, moods, and estimates of systolic blood pressure (SBP) relative to actual SBP levels. Several self-reports and autonomic measures were collected during and after each of 22 tasks. Within-S correlations indicated that all Ss could estimate SBP at levels greater than chance. Further, 68% of the Ss evidenced at least 1 significant symptom–SBP correlation. Although medicated hypertensives believed they could estimate their BP more accurately than other groups, they were actually no more accurate than the other Ss. They also evidenced far fewer empirically derived symptom–SBP and emotion–SBP correlations than any other group. Overall, blood pressure (BP) beliefs were largely inaccurate. If these erroneous beliefs can be eliminated, Ss may be able to estimate BP fluctuations more accurately. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Tumor cells from eight freshly isolated cervical cancers (i.e., four adenocarcinomas and four squamous carcinomas) were analyzed for their production of the immune-inhibitory cytokine transforming growth factor-beta (TGF-beta) in vitro. All fresh adenocarcinomas secreted significant levels of TGF-beta (mean 397, range between 207 and 782 pg/ml/10(5) cells/48 hr). In contrast, no detectable TGF-beta was present in the supernatants from the four fresh squamous carcinoma cultures (P < 0.001). These data suggest that major differences in the secretion of the immunoinhibitory cytokine TGF-beta exist between squamous cell carcinomas and adenocarcinomas of the uterine cervix. Furthermore, these findings suggest that at least some of the differences in the natural biologic behavior, as well as in the response to radiation treatment, between these two histologic types of cervical cancer could be related to differences in secretion of this immune-inhibitory cytokine.  相似文献   
6.
7.
8.
For users of an executive information system (EIS), the EIS interface is the system and is crucial to the EIS's success. These guidelines for designing EIS interfaces are based on studies of actual EIS interfaces that meet the unique information needs of executives.  相似文献   
9.
10.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号