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   105960篇
  免费   6565篇
  国内免费   15篇
  2022年   718篇
  2021年   1552篇
  2020年   1275篇
  2019年   1433篇
  2018年   2671篇
  2017年   2398篇
  2016年   3255篇
  2015年   4298篇
  2014年   4585篇
  2013年   5929篇
  2012年   6890篇
  2011年   6206篇
  2010年   4173篇
  2009年   3447篇
  2008年   5068篇
  2007年   4858篇
  2006年   4678篇
  2005年   3966篇
  2004年   4021篇
  2003年   3536篇
  2002年   3320篇
  2001年   2715篇
  2000年   2507篇
  1999年   2061篇
  1998年   1014篇
  1997年   761篇
  1996年   771篇
  1995年   720篇
  1994年   658篇
  1993年   588篇
  1992年   1243篇
  1991年   1162篇
  1990年   1105篇
  1989年   1170篇
  1988年   970篇
  1987年   991篇
  1986年   911篇
  1985年   956篇
  1984年   785篇
  1983年   703篇
  1982年   589篇
  1979年   796篇
  1978年   600篇
  1975年   696篇
  1974年   754篇
  1973年   714篇
  1972年   655篇
  1970年   621篇
  1969年   687篇
  1968年   646篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
161.
Book review     
  相似文献   
162.
163.
The possibility of using the enzyme-linked immunosorbent assay (ELISA) for the diagnosis of leptospirosis has been shown. This method has proved to be more simple and sensitive than the leptospiral microagglutination and lysis test. The data on obtaining genus-specific leptospiral antigens are presented. As revealed in this study, the antigens obtained by the complex treatment of microbial cells with ultrasound and detergents show the maximum activity in ELISA. The optimum parameters of the ELISA system for the diagnosis of leptospirosis have been established.  相似文献   
164.
165.
166.
167.
In dried oriented samples of purple membrane isolated from Halobacterium halobium, the photoelectric activity decreases and the light adaptation vanishes when the water content of the sample is lowered. In the photocycle the first steps of the proton movement were accelerated with decreasing humidity, while the last steps of the photocycle could not be observed. From the analysis of the photoelectric signal we conclude that at low humidities the protons move forward in the L decay and return to their original place during M decay.  相似文献   
168.
24 patients with non-Hodgkin's lymphomas of low-grade malignancy (stage III and IV) were treated either with a single drug (prednimustine) or with combination chemotherapy (cyclophosphamide, vincristine and prednisone). Response to therapy was similar in both groups. Prednimustine induced complete remission in 6 from 13 patients, while in that group treated with combination chemotherapy a complete remission was recorded in 4 from 11 patients. Both regimens were well tolerated. Therapy with prednimustin has an advantage in oral administration enabling it to be used in out-patient practice.  相似文献   
169.
Recent studies have shown that cells expressing neuronal antigens can be derived from a bone marrow transplant. A new report lends support to and extends these previous results by presenting compelling morphological evidence for the generation and integration of highly differentiated bone marrow-derived neurons.  相似文献   
170.
The trigger calcium hypothesis of signal transmission between T-tubules and terminal cisternae (TC) of the sarcoplasmic reticulum (SR) in twitch muscle fibres implies the presence of calcium along T-tubule membranes at rest and its release upon excitation. To test this hypothesis, calcium was immobilised using a fixing and precipitating solution of glutaraldehyde in phosphate buffer at pH 8.0 and the calcium was substituted for by lead. Simultaneous tension recordings revealed the occurrence of contractions or a burst of twitches upon perfusion with the fixative. Procaine or tetrodotoxin (TTX) was used to inhibit this activity. In fibres without fixative-induced activity, precipitates were observed along T-tubules and in adjoining parts of TC. In activated fibres, tubular and TC precipitates were absent. These results are consistent with the trigger calcium hypothesis. In fibres activated by depolarisation, calcium returned to TC after passing successively through different parts of the SR.  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