全文获取类型
收费全文 | 77265篇 |
免费 | 10901篇 |
国内免费 | 4766篇 |
专业分类
耳鼻咽喉 | 1177篇 |
儿科学 | 1125篇 |
妇产科学 | 1217篇 |
基础医学 | 6798篇 |
口腔科学 | 3466篇 |
临床医学 | 11966篇 |
内科学 | 13087篇 |
皮肤病学 | 908篇 |
神经病学 | 4771篇 |
特种医学 | 3118篇 |
外国民族医学 | 44篇 |
外科学 | 9164篇 |
综合类 | 10235篇 |
现状与发展 | 19篇 |
一般理论 | 5篇 |
预防医学 | 6498篇 |
眼科学 | 1736篇 |
药学 | 6439篇 |
64篇 | |
中国医学 | 3610篇 |
肿瘤学 | 7485篇 |
出版年
2024年 | 345篇 |
2023年 | 1992篇 |
2022年 | 2714篇 |
2021年 | 3450篇 |
2020年 | 3392篇 |
2019年 | 2390篇 |
2018年 | 3325篇 |
2017年 | 3054篇 |
2016年 | 3225篇 |
2015年 | 4255篇 |
2014年 | 5075篇 |
2013年 | 4993篇 |
2012年 | 4785篇 |
2011年 | 5072篇 |
2010年 | 4127篇 |
2009年 | 4037篇 |
2008年 | 3505篇 |
2007年 | 3347篇 |
2006年 | 3534篇 |
2005年 | 3148篇 |
2004年 | 2372篇 |
2003年 | 2559篇 |
2002年 | 2246篇 |
2001年 | 2122篇 |
2000年 | 1769篇 |
1999年 | 1778篇 |
1998年 | 1519篇 |
1997年 | 1411篇 |
1996年 | 1204篇 |
1995年 | 1075篇 |
1994年 | 896篇 |
1993年 | 559篇 |
1992年 | 571篇 |
1991年 | 489篇 |
1990年 | 401篇 |
1989年 | 405篇 |
1988年 | 314篇 |
1987年 | 274篇 |
1986年 | 227篇 |
1985年 | 188篇 |
1984年 | 119篇 |
1983年 | 125篇 |
1982年 | 107篇 |
1981年 | 93篇 |
1980年 | 64篇 |
1979年 | 44篇 |
1978年 | 34篇 |
1977年 | 44篇 |
1976年 | 32篇 |
1975年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Influences on the Selection of Dietetics as a Career 总被引:1,自引:0,他引:1
Objective To gather information on the factors that influence students’ decisions to choose dietetics as a career.Design Self-administered questionnaires regarding the point at which career decisions were made were completed by 1,695 students in Plan IV/V dietetics programs throughout the United States.Subjects All Plan IV/V dietetics programs that reported greater than five graduates in the academic year 1989 to 1990 were selected from the 1990-1991 Directory of Dietetic Programs for the sample population. Of the 156 schools that were mailed questionnaires, responses were received from 84 schools (54%). Almost 90% of the students were women, 10.6% were men.Statistical analyses Data were analyzed using the Statistical Package for the Social Sciences. A χ2 analysis was used to examine the relationship between point of decision and factors that influenced career choice, including people who influence career choice.Results The majority of students (55%) questioned reported making their career decision in college. Students rated interest in nutrition (96.3%) and job enjoyment (93.8%) as factors that were important in their decision to pursue a career in dietetics. College catalogs were rated by 48.3% of the students as being either useful or very useful in helping them make their career selection. With respect to gender differences, women rated a diverse work environment as being very important to their career decision more frequently than men (χ2=15.44, P<.01). Women were more likely than men to rate part-time work opportunities as being very important (χ2=26.75, P<.001); and selected working with people as being very important to their career decision (χ2=17.59, P<.01).Conclusions Findings identified that recruitment strategies need to be audience specific. Because career decision making appears to occur during one of three time frames (high school, college, or work experience), recruitment activities should be developed to specifically target students at these times. One way to increase the exposure of students to the profession of dietetics is for registered dietitians to give guest lectures in introductory college courses and high school upper-class courses in health, home economics, and biology. The use of university/college catalogs as effective marketing tools should also not be underestimated.Data suggest that gender differences exist in factors that influence persons to choose dietetics as a career. To increase the number of men who pursue careers in dietetics, future research should be designed to more fully explore gender differences, so that strategies to recruit more men into the profession can be developed. J Am Diet Assoc. 1997: 97;254–257. 相似文献
73.
74.
75.
经逆转录病毒载体将人GM-CSF基因导入人膀胱癌细胞株BIU-87细胞中,建立了转基因细胞株BIU/GM。经流式细胞仪行细胞DNA周期分析表明GM-CSF基因的导人及表达对BIU-87细胞的增长无影响。免疫荧光测定发现转GM-CSF基因及表达不能促进BIU-87细胞表面HLA-ABC、DR、DQ抗原的表达。转基因瘤细胞株经6000rad X射线照射灭活后,丧失增殖能力,逐步死亡,但能维持一定水平的GM-CSF分泌活性达两周以上。从而为制备灭活的转基因瘤苗提供了初步经验。 相似文献
76.
本文对遵义地区43例鼻咽、鼻腔恶淋巴瘤的临床病理及免疫学表型进行了研究,结果显示:全部病例均为弥漫型,无1例滤泡型,组织学类型以多表细胞性淋巴瘤为主,共33例(包括小细胞型13例,中多形15例,大多形5例),占76.7%。用UCHL-1、CD20和Mac387等多单克隆抗体进行免疫表型研究。显示T细胞淋巴瘤37例(86%),B细胞淋巴瘤4例(9.3%),无1例组织细胞性淋巴瘤。鼻咽部T.B淋巴瘤比 相似文献
77.
Shirley L. Jones RNC MS 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1996,25(9):777-783
Advances in human genetics are rapidly changing the scope of information and care that can be provided to health care consumers. By the year 2005 it is expected that the entire human genome will be mapped and all 70,000–100,000 genes will be identified. Currently, there are more than 5,000 known single-gene disorders. With the movement of specialized health services into the primary care setting, nurses increasingly will need to be knowledgeable about genetic disorders, screening/diagnostic tests, and implications for health care. In addition, the management of genetic information raises issues of informed consent, privacy and confidentiality, truth telling and disclosure, and nondiscrimination. 相似文献
78.
本文以 E.coli CM891为靶细胞,用细菌内抗突变作用模式研究了肉桂醛,鞣酸,二烯丙三硫的抗4NQO 突变性及其作用机制。含质粒 pKM101的 CM891的高抗株(抗50μg/ml 氨苄青霉素)能提高该菌株的自发突变率和4NQO 诱发的突变率以及对鞣酸的杀伤抗性。肉桂醛的抗突变性不依赖质粒 pKM101效应,但与暂时性生长延搁有关。鞣酸及二烯丙三硫的抗突变机制可能包括质粒 pKM101介导的易误修复。上述三种化学物中每二种联合应用均显示抗4NQO 突变性的协同效应及对靶细胞的毒性杀伤作用。 相似文献
79.
粮谷尘致肺损害的实验研究 总被引:2,自引:1,他引:1
粮谷尘为混合性粉尘,含游离SiO29.77%,分离培养出普通高温放线菌。染尘动物肺脏早期病变主要为小灶性肺泡炎、灶性间质性肺炎、异物肉芽肿等,大、中支气管壁脱颗粒肥大细胞增多。90d以后,上述病变明显减少,但逐渐出现少数小的细胞结节,间质轻度纤维组织增生、支气管慢性炎症和小叶中央型肺气肿样病变,观察1a(年)未见明显纤维化。 相似文献
80.
在连续361例患者心内电生理检查中,发现4例有心脏传导的裂隙现象。其特点表现为激动传导方向上远端平面相对不应期(RRP)长,程序刺激中先出现传导延缓,随后近端平面也进入RRP使传导变为延缓,激动经过近端平面延缓传导后,到达远端平面时其已脱离了RRP,使已经在远端传导延缓的情况变为传导正常,与经典的裂隙现象相比,这种裂隙现象的发生机制,与心内电图的表现均有不同,暂定名为变异性裂隙现象。 相似文献