全文获取类型
收费全文 | 712篇 |
免费 | 40篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 17篇 |
2014年 | 24篇 |
2013年 | 69篇 |
2012年 | 39篇 |
2011年 | 50篇 |
2010年 | 18篇 |
2009年 | 25篇 |
2008年 | 47篇 |
2007年 | 52篇 |
2006年 | 35篇 |
2005年 | 45篇 |
2004年 | 43篇 |
2003年 | 39篇 |
2002年 | 29篇 |
2001年 | 2篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 10篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1984年 | 4篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1965年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有752条查询结果,搜索用时 328 毫秒
1.
- Several animal species are known to distinguish between their own eggs and eggs of unrelated conspecifics. However, the cues involved in this discrimination are often unknown. These cues were studied using the predatory mite Gynaeseius liturivorus Ehara.
- Adult females of these predatory mites oviposit in clusters and avoid oviposition close to eggs laid by other females, resulting in reduced cannibalism between offspring. Because predatory mites are blind, it was tested whether volatiles of eggs were used as a cue for egg recognition.
- Adult female predatory mites were offered volatile cues of their own eggs and of unrelated conspecific eggs, and females were prevented from contacting the eggs. Predatory mites oviposited closer to their own eggs than to unrelated eggs. This preference was observed even when one own and one unrelated egg were offered as a volatile source.
- These results suggest that adult female predatory mites can determine kinship using volatiles released from the eggs.
2.
Kiyotaka Chinzei Kantaro Fujioka Hiroshi Kitazato Itaru Koizumi Tadamichi Oba Motoyoshi Oda Hisatake Okada Toyosaburo Sakai Yoshihiro Tanimura 《Marine Micropaleontology》1987,11(4)
Downcore changes in microfossil assemblages and oxygen isotope ratios in three piston cores recovered from the Northwestern Pacific, off central Japan, show that the subtropical Kuroshio front was located to the south of C-4 core site (Lat. 33° N) during the last glacial. The front then advanced northward, passing over the C-4 site and the C-6 site (34.6° N) at about 13 ka and 10 ka, respectively, and reached the C-1 core site (36° N) at about 7 ka. After 5.5 ka it retreated to the area between the C-1 and C-6 sites. A brief but significant cold event, the readvance of the cold Oyashio Current, is recognized between 11 and 10 ka in the two northern cores, but the current did not reach the southern C-4 site. A contemporaneous cold event is known in the North Atlantic, and the cooling was probably a global phenomenon likely to be associated with lowering of sea level. Contamination of isotopically light water is apparent between 14 and 11 ka in the marked change in isotopic composition of benthic foraminifers. Oxygen isotope ratios of planktonic foraminifers show that prior to the advance of the Kuroshio front, the surface water at these core sites was isotopically lighter than the Kuroshio water at that time. 相似文献
3.
Hiroshi Yonemitsu Koichiro Shimomura Motoyoshi Satake Shunji Mochida Masahiko Tanaka Thoru Endo Akira Kaji 《Plant cell reports》1990,9(6):307-310
Hairy roots were obtained following inoculation of the stems of Lobelia inflata L. with Agrobacterium rhizogenes strain ATCC 15834. These hairy roots contained agropine and mannopine. In addition, lobeline was detected by HPLC and confirmed by mass spectrometry. Various media were tested for the growth of hairy roots as well as for the content of lobeline in hairy roots. The growth rate of hairy roots cultured in Nitsch and Nitsch's medium was approximately one third of those cultured in other media. The lobeline content of hairy roots (18–54 g/g dry weight) cultured in these media was the same order of magnitude compared with that of roots of L. inflata (24 g/g dry weight) cultivated in pots. The hairy roots cultured in Nitsch and Nitsch's medium were morphologically different from those cultured in other media.Abbreviations MS medium
Murashige and Skoog's medium
- 1/2 MS medium
one-half strength of the standard Murashige and Skoog's medium
- B5 medium
Gamborg's B5 medium
- NN medium
Nitsch and Nitsch's medium
- FW
fresh weight
- DW
dry weight 相似文献
4.
5.
Masayuki Nakamichi Fumiaki Cho Tetsuhiro Minami 《Primates; journal of primatology》1990,31(2):213-224
This study documents age-related changes in the interactions of wild-born cynomolgus macaque mothers and their infants living
in individual cages during the first 14 weeks of infant life. Body contact between mother and infant, maternal holding, and
infant sucking were found to decrease, and the mothers showed an increased frequency of aggression toward their infants with
age. These results were broadly similar to those reported for mother-infant interactions in other macaques living in social
groups. Nevertheless, a clear difference between the present cynomolgus macaques and other macaques in social groups was apparent.
The cynomolgus macaque mothers tended to permit their infants to move about freely without displaying maternal protectiveness
such as restraint or retrieval, unlike other macaque mothers in social groups. Such maternal behaviors might derive from the
experience of living in individual cages for many years and the relative safety of living in individual cages. The lack of
maternal restraint and retrieval could be responsible for the observed sex differences in behavior: male infants moved more
actively, and broke, and made contact with their mothers more frequently than did female infants. Moreover, mothers of female
infants held and groomed them more frequently and were less aggressive toward them. 相似文献
6.
Kenji Takeuchi Sayumi Shibamoto Makio Hayakawa Takamitsu Hori Keiji Miyazawa Naomi Kitamura Fumiaki Ito 《Experimental cell research》1996,223(2):420
Hepatocyte growth factor (HGF) stimulated cell migration of human gastric carcinoma cell lines MKN1, MKN7, and MKN28. Epidermal growth factor (EGF) also stimulated the cell migration of these three cell lines. In MKN7 cells, HGF-stimulated cell migration was rather reduced in the presence of EGF, whereas such an observation was not made with MKN1 and MKN28 cells. Therefore, we compared the effect of EGF on HGF-stimulated HGF receptor phosphorylation in these cell lines. HGF induced a rapid tyrosine phosphorylation of the HGF receptor in all these cell lines. In MKN7 cells, the increased phosphorylation was further enhanced by EGF, although EGF alone did not affect tyrosine phosphorylation of the HGF receptor. In MKN1 and MKN28 cells, EGF did not influence tyrosine phosphorylation of the HGF receptor, whether HGF was present or not. The data presented here suggest that EGF negatively modulates the cellular response to HGF by increasing tyrosine phosphorylation of the HGF receptor in certain types of epithelial cells, e.g., MKN7 cells. 相似文献
7.
It has been shown that mammalian neurogenesis is partly controlled by multiple basic helix–loop–helix (bHLH) genes, as inDrosophila.Recently, mouse homologs ofDrosophila atonal,a proneural gene encoding a bHLH protein required for chordotonal organ and photoreceptor development, have been characterized to obtain further insights into the molecular nature of mammalian neurogenesis. Here, to assess their potential involvement in genetic neural disorders, we have determined genetic map positions for four mouseatonal-related genes,Atoh1, Atoh2, Atoh3,andNdrf,which encode MATH-1, MATH-2, MATH-3, and NDRF, respectively. Interspecific backcross analysis indicated thatAtoh1andAtoh2were located in separate positions of Chr 6 and thatAtoh3andNdrfwere mapped to Chr 10 and Chr 11, respectively. Thus, these structurally related genes are located separately on multiple chromosomes. 相似文献
8.
Hideaki Sato Hideki Hirayama Takeshi Yamamoto Yoshimasa Lchio Fumiaki Ishizawa Michinao Mizugaki 《Luminescence》1994,9(2):73-77
The purpose of the study was to evaluate the quality of Toki-shakuyaku-san extract granules (TJ-23) using chemiluminescence (CL). A linear relationship was obtained between the log value of the CL of TJ-23 and the reaction temperature. An excellent correlation (r= 0.999) was found between the slope of this curve (ΔA) and the colour intensity due to the browning reaction occurring at the early stage of the Maillard reaction. 相似文献
9.
Kyosuke Mushiake Fumiaki Motoyoshi Naomi Kondo Hiroyuki Shimizu Tadao Orii 《Biotherapy》1993,7(2):101-107
Five patients with common variable immunodeficiency treated in our hospital between December 1979 and December 1990 were given six kinds of intravenous immunoglobulin preparations (pepsin treated, S-sulfonated, polyethylene glycol treated, pH4 treated, alkylated, and pH4.25 formulation preparation) for replacement therapy. Duration of the therapy ranged from 7.6 to 11 years. Incidences of fever and acute infections were variable among patients, but no significant differences were seen in the incidences among periods given each preparation. Three cases revealed abnormal pulmonary functions in tests. Adverse reactions were rarely seen in our study periods, and no severe reactions were observed. No significant differences were seen in incidences of adverse reactions. Postinfusion levels of serum complement slightly decreased from preinfusion levels. However, the decrease in complement was not related to any adverse reaction. No long-term complications such as transmission of hepatitis have been observed. Our data suggest that no obvious differences exist between the efficacy and safety of each IVIG preparation. Differences of efficacy of IVIG replacement therapy may be due to the variable pathophysiology of each patient.Abbreviations CVID
common variable immunodeficiency
- IVIG
intravenous immunoglobulin 相似文献
10.
Cosmid and plasmid clones containing 11 kb, or more, of genomic DNA sequences were mapped with high efficiencies using fluorescence in situ hybridization (FISH) to mitotic metaphase chromosomes prepared from floral tissues of Arabidopsis thaliana. The chromosomal locations were correlated with the map positions determined by RFLP (restriction fragment length polymorphism) analyses. Almost no signals were detected on the chromosomes of root meristematic tissues when FISH was performed with the same clones as probes. This discrepancy in efficiency of detection is possibly caused by the differences in chromatin structure between the root meristematic tissues and the floral tissues. 相似文献