全文获取类型
收费全文 | 245253篇 |
免费 | 22695篇 |
国内免费 | 17060篇 |
专业分类
耳鼻咽喉 | 2250篇 |
儿科学 | 2482篇 |
妇产科学 | 3120篇 |
基础医学 | 28847篇 |
口腔科学 | 4495篇 |
临床医学 | 33977篇 |
内科学 | 35919篇 |
皮肤病学 | 2403篇 |
神经病学 | 13288篇 |
特种医学 | 9173篇 |
外国民族医学 | 143篇 |
外科学 | 24116篇 |
综合类 | 41443篇 |
现状与发展 | 59篇 |
一般理论 | 20篇 |
预防医学 | 15476篇 |
眼科学 | 7243篇 |
药学 | 25310篇 |
228篇 | |
中国医学 | 14341篇 |
肿瘤学 | 20675篇 |
出版年
2024年 | 796篇 |
2023年 | 3820篇 |
2022年 | 9879篇 |
2021年 | 12563篇 |
2020年 | 9417篇 |
2019年 | 8208篇 |
2018年 | 8664篇 |
2017年 | 7766篇 |
2016年 | 7236篇 |
2015年 | 11299篇 |
2014年 | 13935篇 |
2013年 | 12246篇 |
2012年 | 18199篇 |
2011年 | 20260篇 |
2010年 | 12311篇 |
2009年 | 9866篇 |
2008年 | 12954篇 |
2007年 | 12958篇 |
2006年 | 12849篇 |
2005年 | 12751篇 |
2004年 | 7959篇 |
2003年 | 7565篇 |
2002年 | 6289篇 |
2001年 | 5582篇 |
2000年 | 5841篇 |
1999年 | 5974篇 |
1998年 | 3701篇 |
1997年 | 3647篇 |
1996年 | 2923篇 |
1995年 | 2702篇 |
1994年 | 2217篇 |
1993年 | 1406篇 |
1992年 | 1928篇 |
1991年 | 1630篇 |
1990年 | 1318篇 |
1989年 | 1118篇 |
1988年 | 1046篇 |
1987年 | 914篇 |
1986年 | 747篇 |
1985年 | 544篇 |
1984年 | 352篇 |
1983年 | 253篇 |
1982年 | 159篇 |
1981年 | 154篇 |
1980年 | 122篇 |
1979年 | 168篇 |
1977年 | 57篇 |
1975年 | 68篇 |
1974年 | 67篇 |
1972年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
After a comprehensive rernew of the literature on syphilitic
aortitis, Longcope, (1) stated in 1913; ": . . . the presence of spiro:
chetes in these lesions, as might be expected, cannot by any means be
constantly demonstrated with Levaaiti stain. . . . . . . That these
organisms are ''Treponema pallidum seems almost certain thouS:h actual
proof of such by culture from the arterial lesions, a most difficult task,
or direct inoculation into animals, has not as yet been accomplished." 相似文献
32.
A conjugate of antisense oligodeoxynucleotide (AS ODN) covalently linked with deoxorubicin (DOX) was synthesized. Its properties and antitumour activity in human carcinoma DOX resistant cells (KB-A-1) were investigated in vitro. The results showed that the conjugate was strongly stable both in Dulbecco's Phosphate-Buffered Saline (PBS) and in culture medium. The intracellular concentration of the conjugate was higher than that of the AS DON by HPLC analysis. The conjugate showed potent dose-dependent inhibition to the growth of KB-A-1 cells. Chemosensitivity of KB-A-1 cells to DOX was also investigated in vitro. When the cells were first exposed to the conjugate (0.5 microM) and then exposed to DOX for 24 h, the IC50 value of DOX decreased from 21.5 to 2.2 microM. In contrast, when treated with the mixture of the same concentration of the AS ODN with equivalent DOX, the IC50 value of DOX was 16.8 microM. Intracellular DOX concentration was detected in KB-A-1 treatment with the conjugate in vitro by HPLC. The results showed that the intracellular DOX concentration was 6.4-fold increased in KB-A-1 cells treated with the conjugate compared to treatment with DOX alone. In contrast, 1.8-fold increasing was observed when treated with the AS ODN. Western blot analysis showed a significantly decrease in the amount of P-glycoprotein in KB-A-1 cells. These results suggest that the conjugate is effective in reversing multidrug resistance. Certainly, further studies are conducting to explore the antitumour effect of the conjugate in vivo. 相似文献
33.
34.
35.
Chee-Yueh Angie Ho Chun-Yu Chen Min-Wen Yang Hung-Ping Liu 《European journal of cardio-thoracic surgery》2005,28(1):174-175
Functional separation of the lungs may be accomplished by several methods. Patient with restricted mouth opening has limited options for one-lung ventilation. We report the use of wire-guided endobronchial blockade, a new tool for achieving one-lung ventilation in a patient with restricted mouth opening requiring nasotracheal, fiberoptic intubation for esophagectomy and reconstruction with gastric tube substitution. 相似文献
36.
Huimin Wang Changyuan Wang Jihong Yao Kexin Liu 《Blood coagulation & fibrinolysis》2007,18(6):555-558
Fully soluble hemostatic fiber (FHF) is made from cotton yarn through a series of chemical reactions with NaOH and chloroacetic acid. The major component of FHF is carboxymethylcellulose. FHF is a kind of biodegradation macromolecule material that can disassociate into a low-molecular-weight compound or a simple substance by hydrolytic and enzymatic courses. The purpose of the present study is to investigate the hemostatic mechanism of FHF. The study indicated that FHF can stop bleeding by physical, chemical and physiological routes. In the physical route, expansion of carboxymethylcellulose in FHF stops bleeding by forming a mechanical clog after contacting with the blood. In the chemical route, the platelets can quickly aggregate around FHF and stimulate releasing and disaggregating reactions, after contacting with the rough surface of FHF, producing thrombus and hemostasis. In the physiological route, gluey particles with negative charges can activate intrinsic coagulation systems by activating the blood coagulation factor XII after FHF dissolution. 相似文献
37.
A procedure is reported by which high levels of the tricyclic molecule desipramine was modified and conjugated at high density to the carrier molecules keyhole limpet hemocyanin and bovine serum albumin so that these could be used as immunogens in Balb/c mice. Such conjugates generated immune responses with high levels of antibody with specificity for the tricyclic. B cell hybridomas generated by fusion of immune Balb/c splenocytes to NS-1 cells which secreted monoclonal antibodies with specificity for the tricyclic were selected in a standard ELISA. In this report, we show that the binding constants of these monoclonal antibodies with various haptens can be assessed accurately by measuring fluorescence polarization, that a high degree of cross-reactivity between the monoclonals and various tricyclics exists, and that this procedure can be used to generate monoclonal antibodies of high binding constants. 相似文献
38.
四氧嘧啶诱发糖尿病大鼠血管紧张素的变化 总被引:1,自引:0,他引:1
实验观察了四氧嘧啶诱发糖尿病大鼠连续饲养110d后体内肾素一血管紧张素系统的变化。结果表明,血浆和心脏的血管紧张素Ⅱ含量无明显变化,而肾脏的AngⅡ含量却明显低于正常对照组。另外,心脏的心钠素(ANP)含量在糖尿病大鼠与正常对照组之间无差别,血中的糖化血红蛋白含量基本无变化。上述结果表明,糖尿病大鼠早期心脏可能无明显损伤,而肾脏的肾素一血管紧张素系统活性降低。 相似文献
39.
40.
螺旋神经节神经元原代培养及其免疫细胞化学鉴定 总被引:8,自引:1,他引:7
孙建军 《中华耳鼻咽喉科杂志》1998,33(4):196-198
目的 建立成体哺乳动物耳蜗螺旋神经节神经元(SGN)体外培养的细胞模型。方法 对出生后7d的Wistar大鼠的螺旋神经节细胞进行解离与分散培养。用荧光显微镜与倒置相差显微镜观察原代培养SGN细胞的活力以及生长与分化过程。应用链霉卵白素过氧化物酶(SP)方法和抗神经丝蛋白单克隆抗体(NFP-McAb)对SGN进行免疫细胞化学染色鉴定。结果 幼龄Wistar大鼠的SGN在体外条件下,可良好存活并有正常 相似文献