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   89616篇
  免费   2635篇
  国内免费   48篇
  2018年   1033篇
  2017年   1220篇
  2016年   2926篇
  2015年   6260篇
  2014年   5864篇
  2013年   5719篇
  2012年   5171篇
  2011年   2491篇
  2010年   2284篇
  2009年   2186篇
  2008年   1003篇
  2007年   985篇
  2006年   1021篇
  2005年   7104篇
  2004年   5779篇
  2003年   3957篇
  2002年   1466篇
  2001年   1119篇
  2000年   371篇
  1999年   1533篇
  1998年   410篇
  1997年   224篇
  1992年   2003篇
  1991年   2061篇
  1990年   2110篇
  1989年   2037篇
  1988年   1975篇
  1987年   1850篇
  1986年   1647篇
  1985年   1680篇
  1984年   1128篇
  1983年   859篇
  1982年   493篇
  1981年   459篇
  1980年   417篇
  1979年   1098篇
  1978年   797篇
  1977年   629篇
  1976年   659篇
  1975年   893篇
  1974年   1013篇
  1973年   1019篇
  1972年   961篇
  1971年   933篇
  1970年   822篇
  1969年   834篇
  1968年   734篇
  1967年   755篇
  1966年   586篇
  1965年   435篇
排序方式: 共有10000条查询结果,搜索用时 976 毫秒
211.
Prophylactic activity and side action of antiinfluenza lactoglobulin were studied under conditions of controlled epidemiological trial in 6361 persons during the epidemiological rise of influenza incidence. The data obtained pointed to the absence of any protective effect of antiinfluenza lactoglobulin. Marked allergenic properties of lactoglobulin and development of sensitization in the persons under observation were found during the study of the side-effect of the preparation. Thus, the absence of prophylactic efficacy and the sensitizing action of antiinfluenza lactoglobulin pointed to the inexpediency of its use for prophylactic and therapeutic purpose.  相似文献   
212.
213.
The published and authors' data have been summarized on (1) the spectrum and properties of crystallins in different amphibian species, (2) localization and synthesis of crystallins in different cellular compartments of the adult amphibian lens, (3) dynamics of crystallin formation during embryogenesis and (4) lens regeneration from tissues of the larval and adult amphibian eyes. The necessity of more detailed studies of crystallin synthesis during embryogenesis and lens regeneration using molecular biological and biochemical methods is stressed. The significance of this approach is illustrated by the pioneering data of Soviet scientists on crystallin polypeptides and corresponding mRNAs in development of Rana temporaria obtained with the use of DNA-RNA hybridization and immunoelectroblotting.  相似文献   
214.
S Bl?hser 《Histochemistry》1988,88(3-6):309-312
The ACTH-immunoreactive (ir) system of the avian brain is particularly conspicuous in the male white-crowned sparrow (Zonotrichia leucophrys gambelii). The irperikaryal population is concentrated mainly within the tuberal region, projecting primarily in a dorsal direction: (i) into the striatum; (ii) into rostral diencephalic, septal, hyperstriatal, and thalamic areas; and (iii) into dorsal and ventral areas of the brain stem. Ir-fibers seemingly contact local non-immunoreactive neurons mainly in the accumbens nucleus, septum, dorsal thalamic nuclei, infundibular and interpeduncular nuclei, and in the rostral diencephalon. Neurohemal zones are not supplied by ACTH-ir terminals. Immunocytochemical problems arising from the complexity of the proopiomelanocortin molecule and its derived peptide components are discussed in relation to phylogenetically directed studies, and contradictory results.  相似文献   
215.
Aims of this study were to analyze the long-term effects of postovulatory aging of mouse oocytes on 1) reproductive traits of parental (F(0)) and first (F(1))-generation females (pregnancy rate, gestation length, litter size, perinatal death, and sex ratio of offspring) and 2) developmental and behavioral variables of F(1) and second-generation (F(2)) offspring (birth weight and weight gain during preweaning development, postnatal day of attainment of immediate righting, spontaneous motor activity, and passive and active conditioned learning ability). Hybrid (C57BL/6JIco x CBA/JIco) females were artificially inseminated at 13 h (control group) or 22 h (oocyte-aged group) after GnRH injection. Experimental (oocyte-aged group) F(0) females exhibited lower pregnancy rate, shortened gestation length, decreased litter size, higher perinatal death of their pups, and increased percentage of male offspring compared to control F(0) females. Postovulatory aging of oocytes was also associated with increased number of growth-retarded pups, delayed development of the righting reflex, and higher spontaneous motor activity and emotionality of F(1) offspring. Postovulatory aging of F(0) oocytes did not affect birth weight, weight gain during preweaning development, passive and active conditioned learning ability of F(1) offspring, or reproductive traits of F(1) females or developmental and behavior variables of F(2) offspring.  相似文献   
216.
The capacity of spleen, thymus, and bone marrow cells of intact (control) and of hydrocortisone-treated mice CBA to induce the lymph node type of graft-v-host reaction (GVHR) in hybrids F1 (CBA X c57bl) was studied. After hydrocortisone injection (2.5 mg per mouse) the donor spleen cells became more active in GVHR, considering the value of lymph node indices and immunoblast content in the regional lymph node as compared with a control group. Following transplantation of thymus cells taken from the hydrocortison-treated donors the immunoblast count was higher, although the lymph node weight remained the same as in the control group. On the contrary, following the transfer of the bone marrow cells from the hydrocortisone-treated mice the lymph nodes enlarged, while the immunoblast count remained as low as in control. Consequently, exogenously conditioned increase in the hydrocortisone level was accompanied by an enrichment of the spleen and thymus cell populations with T-lymphocytes, proliferating in response to H-alloantigens.  相似文献   
217.
218.
219.
220.
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