全文获取类型
收费全文 | 6837篇 |
免费 | 717篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 65篇 |
儿科学 | 332篇 |
妇产科学 | 83篇 |
基础医学 | 806篇 |
口腔科学 | 164篇 |
临床医学 | 682篇 |
内科学 | 1307篇 |
皮肤病学 | 368篇 |
神经病学 | 457篇 |
特种医学 | 470篇 |
外科学 | 991篇 |
综合类 | 178篇 |
一般理论 | 8篇 |
预防医学 | 518篇 |
眼科学 | 44篇 |
药学 | 451篇 |
中国医学 | 3篇 |
肿瘤学 | 657篇 |
出版年
2021年 | 72篇 |
2019年 | 78篇 |
2018年 | 94篇 |
2017年 | 62篇 |
2016年 | 78篇 |
2015年 | 84篇 |
2014年 | 106篇 |
2013年 | 144篇 |
2012年 | 197篇 |
2011年 | 201篇 |
2010年 | 163篇 |
2009年 | 142篇 |
2008年 | 228篇 |
2007年 | 253篇 |
2006年 | 262篇 |
2005年 | 245篇 |
2004年 | 227篇 |
2003年 | 243篇 |
2002年 | 192篇 |
2001年 | 207篇 |
2000年 | 226篇 |
1999年 | 213篇 |
1998年 | 128篇 |
1997年 | 141篇 |
1996年 | 155篇 |
1995年 | 123篇 |
1994年 | 93篇 |
1993年 | 92篇 |
1992年 | 161篇 |
1991年 | 192篇 |
1990年 | 181篇 |
1989年 | 174篇 |
1988年 | 212篇 |
1987年 | 186篇 |
1986年 | 159篇 |
1985年 | 199篇 |
1984年 | 114篇 |
1983年 | 123篇 |
1982年 | 74篇 |
1981年 | 71篇 |
1980年 | 62篇 |
1979年 | 109篇 |
1978年 | 101篇 |
1977年 | 82篇 |
1976年 | 79篇 |
1975年 | 72篇 |
1974年 | 93篇 |
1973年 | 100篇 |
1972年 | 72篇 |
1971年 | 72篇 |
排序方式: 共有7584条查询结果,搜索用时 15 毫秒
91.
Paulsen RD Steinberg GK Norbash AM Marcellus ML Lopez JR Marks MP 《Neurosurgery》1999,44(3):479-84; discussion 484-6
92.
93.
94.
Marks R 《Focus (San Francisco, Calif.)》1996,11(10):5-6
Oral sex continues to be a source of confusion in determining its risk for HIV transmission. Educator Dave Nimmons concludes that oral sex offers a possible, but very low, risk of HIV infection and states that much of the concern about oral sex and HIV prevention centers around two dozen cases of single occurrences of oral transmission from all over the world. Many researchers believe that knowledge about this small number of cases facilitates informed decisions about risk and demonstrates under which conditions transmission is possible. There is concern, however, that because a single case can personalize an issue, it can have a more powerful effect on an individual's imagination than a study with many participants. To reduce HIV transmission risk, researcher Paul O'Malley suggests avoiding trauma to the mouth and throat, especially vigorous or prolonged oral sex, avoiding oral sex when infections or abrasions in the mouth and throat are present, and avoiding the use of stimulant substances that dull sensation. At the Vancouver conference, there was little disagreement from a panel of experts that oral sex is an extremely low-risk activity. Researcher Traux presented results from a multivariate analysis of risk assessment data from HIV-antibody testing interviews and found that anal sex and drug use were associated with increased seroprevalence and oral sex was not. Interestingly, there was no statistically significant difference in seroprevalence rates between people who used condoms during oral sex and those who did not. The panels also discussed a recent study in which six out of seven rhesus monkeys became infected with simian immunodeficiency virus (SIV) after it was dabbed on the back of their mouths. Effective counselors and educators can work to raise consciousness about the actual risk of transmission from oral sex, determine whether an individual can increase or decrease this risk, determine the meaning of oral sex in a person's life, and the extent to which the person is comfortable taking any risk. 相似文献
95.
Summary A radioimmunoassay for the semi-synthetic podophyllotoxin VP16-213 has been developed which is suitable for pharmacokinetic studies of the drug. A high titre antiserum was produced in a sheep in response to a VP16-213-BSA conjugate prepared using sodium periodate. Podophyllotoxin does not cross-react with the antiserum and VM26 cross-reacts to only a small extent (<0.6%). In the absence of a high specific activity tritium label, a radioiodinated histamine ligand was produced which was only partially displaced from antibody by native drug. VP16-213 can be measured in plasma without prior drug extraction with a theoretical limit of detection of 5–10 g/l. VP16-213 cis (picro) hydroxy acid is recognised by the antiserum to a greater extent than the drug itself. Thus, in order to eliminate any interference from the trans hydroxy acid metabolite chloroform extraction of plasma samples was carried out. 相似文献
96.
Surface marker studies were performed on "hairy cells" from 7 patients with hairy cell leukemia (HCL). Using sensitive analytic techniques including specific antisera and Fluorescence Activated Cell Sorter (FACS-1), further definition of the abnormal cell was achieved. Four different antisera were used in infestigating the cell surface characteristics of these patients: anti-p23,30, an antiserum reactive with B cells and a subset of monocytes, anti-311, which reacts only with T cells, pepsin digested anti-F(ab')2 which reacts with B cells only and pepsin digested anti-lysozyme reactive with monocytes and myeloid cells, but not with B or T cells. In all cases strong reactivity was observed with anti-p23,30 and anti-F(ab')2, but no reactivity with anti-311. Five out of the seven cases were reactive with anti-lysozyme in a pattern similar to normal monocytes. Furthermore, when cells were separated according to binding to anti-p23,30, anti-F(ab')2 and anti-lysozyme and in two cases, according to cell size, the majority of reactivity and large cells were "hairy" when examined under microscopy. In contrast, the small and nonreactive (dull cells) appeared as normal mature lymphocytes. Thus, our data supports the view that HCL cells bear in most cases B cell and monocytic membrane markers. 相似文献
97.
98.
99.
Stoodley MA Thompson RC Mitchell RS Marks MP Steinberg GK 《Neurosurgery》2000,46(4):841-51; discussion 851-2
100.