全文获取类型
收费全文 | 11513篇 |
免费 | 1113篇 |
国内免费 | 14篇 |
出版年
2022年 | 81篇 |
2021年 | 191篇 |
2020年 | 102篇 |
2019年 | 114篇 |
2018年 | 164篇 |
2017年 | 129篇 |
2016年 | 257篇 |
2015年 | 427篇 |
2014年 | 435篇 |
2013年 | 546篇 |
2012年 | 718篇 |
2011年 | 725篇 |
2010年 | 469篇 |
2009年 | 388篇 |
2008年 | 552篇 |
2007年 | 612篇 |
2006年 | 544篇 |
2005年 | 466篇 |
2004年 | 473篇 |
2003年 | 461篇 |
2002年 | 441篇 |
2001年 | 208篇 |
2000年 | 185篇 |
1999年 | 221篇 |
1998年 | 125篇 |
1997年 | 109篇 |
1996年 | 106篇 |
1995年 | 107篇 |
1994年 | 90篇 |
1993年 | 91篇 |
1992年 | 148篇 |
1991年 | 138篇 |
1990年 | 150篇 |
1989年 | 123篇 |
1988年 | 147篇 |
1987年 | 121篇 |
1986年 | 125篇 |
1985年 | 138篇 |
1984年 | 138篇 |
1983年 | 120篇 |
1982年 | 125篇 |
1981年 | 104篇 |
1980年 | 104篇 |
1979年 | 115篇 |
1978年 | 93篇 |
1977年 | 89篇 |
1976年 | 76篇 |
1975年 | 84篇 |
1974年 | 67篇 |
1973年 | 79篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Monoclonal antibody as a probe for structure and function of an Escherichia coli outer membrane protein 总被引:16,自引:0,他引:16
Eight independently derived monoclonal antibodies directed against the LamB protein were produced and characterized. By using these antibodies as probes, we identified four distinct topological and functional regions in the LamB molecule. Four monoclonal antibodies recognize antigenic determinants of the protein exposed on the outer side of the membrane. Two of these have their binding sites located in a region involved in maltose transport. One monoclonal antibody presumably binds to a determinant which is normally hidden in the membrane and three monoclonal antibodies recognize determinants facing the periplasmic space. 相似文献
3.
4.
5.
6.
Victor Horsley 《BMJ (Clinical research ed.)》1910,1(2568):725-726
7.
Jin Wei Mia Madel Alfajaro Peter C. DeWeirdt Ruth E. Hanna William J. Lu-Culligan Wesley L. Cai Madison S. Strine Shang-Min Zhang Vincent R. Graziano Cameron O. Schmitz Jennifer S. Chen Madeleine C. Mankowski Renata B. Filler Neal G. Ravindra Victor Gasque Fernando J. de Miguel Ajinkya Patil Huacui Chen Craig B. Wilen 《Cell》2021,184(1):76-91.e13
- Download : Download high-res image (212KB)
- Download : Download full-size image
8.
Victor F. Medina Peter M. Jeffers Steven L. Larson Waleska Perez 《International journal of phytoremediation》2000,2(4):287-295
Bleach treatment of plants was studied as a simple alternative to axenic tissue cultures for demonstrating phytodegradation of aqueous and gas-phase environmental contaminants. Parrotfeather (Myriophyllum aquaticum), spinach (Spinacia oleracea), and wheat (Triticum aestivum) were exposed to 0.525% NaC10 solutions for 15 s, then rinsed in deionized water. Plate counts indicated that 97 to 100% of viable bacteria were removed from parrotfeather and spinach. Transformation rates for 2,4,6-trinitrotoluene (TNT) by bleached and untreated parrotfeather were virtually identical. Similarly, treated and untreated spinach, wheat heads, and wheat leaves removed methyl bromide (MeBr) from air at the same rates. However, wheat root with attendant adhering soil was rendered inactive by bleach treatment. Parrotfeather roots examined by dissecting microscope and by electron microscope showed no significant damage caused by bleach treatment. 相似文献
9.
A group of captive chimpanzees, consisting of one adult male and three mother/infant pairs, was systematically observed over a 15-month period. Over 200 hr of data were collected, using both sequential and time sampling techniques, and compared to the available data on wild chimps. Unlike many captive groups, most behavior patterns were remarkably similar, both qualitatively and quantitatively, to that of wild chimpanzees including: play, grooming, infant sexual development, tool use, food sharing, prosocial partner preferences, and aggressive displays. 相似文献
10.
Little is known regarding the role of androgenic hormones in the maintenance of myosin heavy chain (MHC) composition of rodent masticatory muscles. Because the masseter is the principal jaw closer in rodents, we felt it was important to characterize the influence of androgenic hormones on the MHC composition of the masseter. To determine the extent of sexual dimorphism in the phenotype of masseter muscle fibers of adult (10-mo-old) C57 mice, we stained tissue sections with antibodies specific to type IIa and IIb MHC isoforms. Females contain twice as many fibers containing the IIa MHC as males, and males contain twice as many fibers containing the IIb MHC as females. There is a modest amount of regionalization of MHC phenotypes in the mouse masseter. The rostral portions of the masseter are composed mostly of type IIa fibers, whereas the midsuperficial and caudal regions contain mostly type IIb fibers. Using immunoblots, we showed that castration results in an increase in the expression of type IIa MHC fibers in males. Ovariectomy has no effect on the fiber type composition in females. We conclude that testosterone plays a role in the maintenance of MHC expression in the adult male mouse masseter. 相似文献