全文获取类型
收费全文 | 993篇 |
免费 | 72篇 |
国内免费 | 3篇 |
出版年
2018年 | 10篇 |
2016年 | 7篇 |
2015年 | 15篇 |
2014年 | 11篇 |
2013年 | 77篇 |
2012年 | 37篇 |
2011年 | 33篇 |
2010年 | 23篇 |
2009年 | 23篇 |
2008年 | 27篇 |
2007年 | 39篇 |
2006年 | 34篇 |
2005年 | 41篇 |
2004年 | 50篇 |
2003年 | 38篇 |
2002年 | 47篇 |
2001年 | 27篇 |
2000年 | 29篇 |
1999年 | 14篇 |
1998年 | 12篇 |
1997年 | 9篇 |
1996年 | 15篇 |
1995年 | 16篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 20篇 |
1991年 | 18篇 |
1990年 | 25篇 |
1989年 | 22篇 |
1988年 | 27篇 |
1987年 | 24篇 |
1986年 | 31篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 12篇 |
1981年 | 14篇 |
1980年 | 22篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1973年 | 8篇 |
1970年 | 6篇 |
1969年 | 7篇 |
1968年 | 13篇 |
1967年 | 6篇 |
1966年 | 5篇 |
1965年 | 5篇 |
排序方式: 共有1068条查询结果,搜索用时 15 毫秒
241.
Osamu Sato Takeyasu Maeda Shigeo Kobayashi Toshihiko Iwanaga Tsuneo Fujita Yasuo Takahashi 《Cell and tissue research》1988,251(1):13-21
Summary Nervous elements in the periodontal ligament and dental pulp of rat incisors were investigated by means of immunohistochemistry for neurofilament protein (NFP) and glia-specific S-100 protein. The periodontal ligament in the incisors was densely innervated by NFP-immunoreactive nerve fibers; the distribution of the nerve fibers and their terminations differed markedly from those in molars. NFP-positive, thick nerve bundles entered the lingual periodontal ligament through slits located in the mid-region of the alveolar socket, and immediately formed numerous Ruffini-like corpuscles. In the labial periodontal ligament, all of the NFP-immunoreactive nerve fibers terminated in free endings. The restricted location of the stretch receptor, Ruffini-like corpuscle, in the lingual periodontal ligament appears to be an essential element, because this region is regularly extended during mastication. The nervous elements were restricted to the alveolar half of the periodontal ligament in every region; they avoided the dental half of the periodontal ligament, which presumably moves continuously with the tooth. Pulpal nerve fibers in incisors also showed a characteristic distribution different from those in molars; individual nerve fibers with beaded structures ran in the center of the pulp toward the incisai edge, and did not form the subodontoblastic nerve plexus of Raschkow.Immunostaining for S-100 protein revealed a distribution pattern of nervous elements similar to that for NFP, suggesting that the nerves supplying the periodontal ligament and dental pulp were mostly covered by a Schwann sheath. 相似文献
242.
K Motomura I Nishisho S Takai H Tateishi M Okazaki M Yamamoto T Miki T Honjo T Mori 《Genomics》1988,2(2):180-184
Mitotic events leading to the loss of the normal allele corresponding to a mutated gene are important for tumorigenesis in rare heritable tumors such as retinoblastoma and Wilms tumor. As reported for both colorectal and breast cancers, some common tumors seem to develop because of the same mitotic events. We examined constitutional and tumor genotypes defined by polymorphic DNA clones in 36 patients with gastric cancer. In 14 cases, constitutional heterozygosity at loci on chromosome 13 had been lost. Loss of alleles was also detected at a locus on chromosome 18 in two cases and at a locus on chromosome 17 in one case. The frequent loss of alleles at loci on chromosome 13 (41%) suggests that elimination of genes on this chromosome may be of importance in the tumorigenesis of human primary gastric cancers. 相似文献
243.
Dr. Tatsuo Ushiki Toshihiko Iwanaga Toru Masuda Yasuo Takahashi Tsuneo Fujita 《Cell and tissue research》1984,235(3):509-514
Summary The present study deals with the localization and ultrastructure of S-100-immunoreactive cells in the human thymus. These immunoreactive cells are distributed mainly in the medulla with some scattered elements in the cortex. Electron-microscopic observation revealed that the cells are characterized by an irregularly shaped nucleus, tubulovesicular structures in the cytoplasm and characteristic interdigitations of the plasma membrane. The cells often embrace lymphocytes with their branched processes. On the basis of these morphological features, the immunostained elements were identified as interdigitating cells (IDCs). The immunocytochemistry for S-100 visualizes the precise distribution and extension of the IDCs under the light microscope and indicates that the IDCs form no structural networks such as those established by the thymic epithelial cells. Since the IDCs in human lymph nodes have also been reported to contain S-100-like immunoreactivity, S-100 protein can be regarded as a useful marker for identifying the IDCs in the human thymus and other lymphoid organs. 相似文献
244.
Summary Adrenal glands of human fetuses were investigated by means of an immunohistochemical method with the use of an anti-S-100 serum. S-100-immunoreactivity was recognized in sustentacular cells located among the chromaffin cells. A characteristic circular arrangement of the immunostained cells was found in the central region of the adrenal glands. It surrounded aggregations of non-argyrophilic, small, round cells, which were identified as the remaining sympathoblasts (primitive sympathetic cells). 相似文献
245.
H Hayashida T Miyata Y Yamawaki-Kataoka T Honjo J Wels F Blattner 《The EMBO journal》1984,3(9):2047-2053
The nucleotide sequences of the immunoglobulin heavy-chain constant region genes of mouse, C gamma 3, C gamma 1, C gamma 2b and C gamma 2a, together with that of a human equivalent C gamma 4 were compared. All the six pairs of genes within the mouse C gamma gene family contain DNA segments that exhibit marked homology, whereas no such segmental homology was found in interspecies comparisons. This result indicates that the four C gamma genes of the mouse evolved concertedly by exchanging parts of their genetic information with each other either by gene conversion or by double unequal crossing-over. Another example of such concerted evolution was found in gene regions encoding membrane domains of the mouse C gamma chains. We also searched for such segmental homologies in other mammalian C gamma gene families and found at least two more examples in man and guinea-pig. In the mouse C gamma gene family, the silent positions of an exon encoding the third domain of C gamma chains show much greater divergence in sequence than other regions, indicating that the genetic information encoded by this gene region was least scrambled during recent evolution. A phylogenetic tree constructed from the nucleotide differences of this exon demonstrates that at least two C gamma genes had already existed before mammalian radiation. Based on these results, evolution of mammalian C gamma gene families is discussed. 相似文献
246.
247.
248.
Immunoglobulin kappa type light chain mRNA (Lkappa mRNA) accumulated in parallel with secretion of immunoglobulin M in cultured mouse spleen cells activated by lipopolysaccharide. Actinomycin D suppressed the accumulation of kappa chain mRNA completely without affecting the degradation rate of kappa chain mRNA. The half life of kappa chain mRNA was about 9 h. Available evidence indicates that lipopolysaccharide stimulates de novo synthesis of kappa chain mRNA. The accumulation of kappa chain mRNA was markedly suppressed by inhibitors of DNA or protein synthesis such as hydroxyurea, cytosine arabinoside and cycloheximide. 相似文献
249.
250.
Congenital polycystic kidney disease was diagnosed at necropsy in a stillborn male cynomolgus monkey (Macaca fascicularis). This case was very similar to infantile polycystic kidney disease in man and the rhesus monkey, except that no increase in number of intrahepatic bile ducts was observed. 相似文献