全文获取类型
收费全文 | 798篇 |
免费 | 56篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 20篇 |
妇产科学 | 6篇 |
基础医学 | 49篇 |
口腔科学 | 45篇 |
临床医学 | 56篇 |
内科学 | 118篇 |
皮肤病学 | 18篇 |
神经病学 | 212篇 |
特种医学 | 145篇 |
外科学 | 69篇 |
综合类 | 27篇 |
预防医学 | 23篇 |
眼科学 | 7篇 |
药学 | 38篇 |
中国医学 | 1篇 |
肿瘤学 | 34篇 |
出版年
2023年 | 7篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 18篇 |
2015年 | 24篇 |
2014年 | 16篇 |
2013年 | 23篇 |
2012年 | 18篇 |
2011年 | 40篇 |
2010年 | 27篇 |
2009年 | 37篇 |
2008年 | 26篇 |
2007年 | 46篇 |
2006年 | 17篇 |
2005年 | 18篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 6篇 |
1998年 | 21篇 |
1997年 | 38篇 |
1996年 | 33篇 |
1995年 | 20篇 |
1994年 | 16篇 |
1993年 | 22篇 |
1992年 | 6篇 |
1991年 | 16篇 |
1990年 | 6篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 18篇 |
1986年 | 18篇 |
1985年 | 20篇 |
1984年 | 11篇 |
1983年 | 17篇 |
1982年 | 9篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 8篇 |
1973年 | 9篇 |
1971年 | 7篇 |
排序方式: 共有871条查询结果,搜索用时 0 毫秒
41.
本文研制了以四苯硼—唐松草新碱缔合物为电活性物质的变价态唐松草新碱—PVC膜电极。电极膜按电活性物质:PVC:DBP为1:8:8组成。该电极在pH 5.0~6.0,Ⅰ=0.05的NaCl—HCl溶液中Nernst响应范围为1×10-3~1×10-5mol/L。电极斜率为58.2 mV/logc。检测限为2.5×10-6mol/L。用直接电位法考察了TDH+,TDH2CF++共存时溶液pH和电极斜率S的关系。用S—pH关系,测定了25℃,Ⅰ=0.05时的Ka1值为(2.5±0.2)×10-4,用E—pH关系,测定了25℃,Ⅰ=0.05时的Ka2值为(8.1±0.9)×10-8。 相似文献
42.
43.
44.
45.
Biosynthesis and secretion of factor VII, protein C, protein S, and the Protein C inhibitor from a human hepatoma cell line 总被引:7,自引:0,他引:7
Using specific radioimmunoassays, 8 day cultures of Hep G2 cells were shown to contain in their supernatants 16, 74, and 828 ng/mL and in their cell lysates, 8, 55, and 48 ng/2 X 10(8) cells of factor VII, protein C, and protein S, respectively. These proteins and the protein C inhibitor were functionally active, and each of these activities was neutralized by their respective polyclonal antibodies. Although vitamin K had a modest effect, warfarin decreased the activity of secreted factor VII, protein C, and protein S by 50% to 90%. Protein C and protein S antigens were reduced three- to fourfold by warfarin. The protein C inhibitor antigen and activity were unaffected by vitamin K or warfarin treatment. Intrinsic labeling and immunoprecipitation indicated that factor VII, protein S, and the protein C inhibitor were secreted as 52,000, 77,000, and 58,000 molecular weight (mol wt) proteins, respectively. Protein C was secreted as a single-chain protein of about 65,000 mol wt, indicating that all of the vitamin K- dependent proteins are translated and secreted as single-chain molecules. Each of the four proteins studied represented their plasma protein counterparts structurally, functionally, and immunochemically. Thus, all of the known soluble components of the protein C pathway are produced by liver parenchymal cells. 相似文献
46.
47.
48.
Stimulation of the hypothalamic paraventricular nucleus produces analgesia not mediated by vasopressin or endogenous opioids 总被引:5,自引:0,他引:5
Raz Yirmiya Shamgar Ben-Eliyahu Yehuda Shavit Przemyslaw Marek John C. Liebeskind 《Brain research》1990,537(1-2):169-174
The analgesic effect of electrical stimulation of the hypothalamic paraventricular nucleus (PVN) was studied. Additionally, the involvement of vasopressin and opioid peptides in this process was examined by comparing vasopressin-deficient (Brattleboro) and Long-Evans rats and by administering the opiate antagonist naloxone. Rats were chronically implanted with a stimulating electrode in the parvocellular (PVN-Pc) and magnocellular (PVN-Mg) divisions of the PVN. At least 10 days after surgery, the analgesic effects of PVN stimulation were examined in lightly anesthetized rats, using the tail-flick method, and in unanesthetized rats, using the hot-plate test. PVN stimulation produced marked analgesia in both tests. Current threshold for analgesia was lower from PVN-Pc than from PVN-Mg. Threshold did not differ significantly between Brattleboro and Long-Evans rats and was not affected by naloxone administration. The results indicate that the PVN is part of the brain's pain inhibitory system, and show that the analgesia induced by PVN stimulation is not mediated by either vasopressin or opioid peptides. 相似文献
49.
50.
Nocardiosis of the lung: chest radiographic findings in 21 cases 总被引:4,自引:0,他引:4
Pulmonary manifestations of nocardial infection were present in 21 patients, with microbiologic proof in all and pathologic proof in 12. An analysis of the findings in these patients, combined with a review of previous reports of nocardiosis, suggests several important conclusions for radiologists. First, nocardiosis may occur in otherwise healthy persons but is most common in compromised patients, especially those being treated with anti-inflammatory agents, particularly corticosteroids, for chronic obstructive pulmonary disease and other systemic diseases. As pathologic manifestations are both suppurative and granulomatous, the chest radiographic manifestations are pleomorphic and not specific. Consolidations and large irregular nodules, often cavitary, are most common; nodules, masses, and interstitial patterns also occur. Pleural effusions are quite common, and lymph nodes may be enlarged. Difficulty and slowness of culture growth, along with the lack of a serologic test for nocardiosis, necessitate its inclusion in the differential diagnosis for both compromised and noncompromised patients in whom an apparent pulmonary infection cannot be rapidly diagnosed. 相似文献