全文获取类型
收费全文 | 1774篇 |
免费 | 150篇 |
国内免费 | 215篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 2篇 |
妇产科学 | 2篇 |
基础医学 | 26篇 |
口腔科学 | 5篇 |
临床医学 | 24篇 |
内科学 | 37篇 |
皮肤病学 | 4篇 |
神经病学 | 16篇 |
特种医学 | 11篇 |
外科学 | 4篇 |
综合类 | 282篇 |
预防医学 | 13篇 |
眼科学 | 2篇 |
药学 | 735篇 |
中国医学 | 953篇 |
肿瘤学 | 22篇 |
出版年
2024年 | 6篇 |
2023年 | 41篇 |
2022年 | 48篇 |
2021年 | 75篇 |
2020年 | 60篇 |
2019年 | 67篇 |
2018年 | 67篇 |
2017年 | 96篇 |
2016年 | 90篇 |
2015年 | 83篇 |
2014年 | 123篇 |
2013年 | 176篇 |
2012年 | 149篇 |
2011年 | 180篇 |
2010年 | 92篇 |
2009年 | 82篇 |
2008年 | 72篇 |
2007年 | 81篇 |
2006年 | 64篇 |
2005年 | 50篇 |
2004年 | 59篇 |
2003年 | 56篇 |
2002年 | 25篇 |
2001年 | 24篇 |
2000年 | 18篇 |
1999年 | 20篇 |
1998年 | 22篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 13篇 |
1994年 | 21篇 |
1993年 | 16篇 |
1992年 | 12篇 |
1991年 | 14篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 17篇 |
1987年 | 10篇 |
1986年 | 5篇 |
1985年 | 13篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1976年 | 3篇 |
1974年 | 1篇 |
排序方式: 共有2139条查询结果,搜索用时 31 毫秒
101.
目的研究氮、磷、钾肥对益母草生长发育及次生代谢物的影响。方法采用大田试验与室内分析相结合的方法。结果益母草各项生长、产量及水苏碱和总生物碱的量基本均为复肥型高于单肥型,复肥型中又以营养平衡型大于营养失调型,但单施氮肥对以上各项指标均有很大促进作用。在复肥型中,足量磷元素与氮元素的合理配施可以提高氮的肥效。结论以益母草株高、叶片数、分蘖数、产量及水苏碱和总生物碱的量为评价标准,根据氮、磷、钾二次肥料数学模型的计算结果,确定最佳施肥量为:N:37.5~44.0g/m^2,P:37.4~54.3g/m^2,K:31.6~34.4g/m^2,氮、磷、钾的最佳配比为4:4.5:3.3。 相似文献
102.
S. Ratsimamanga-Urverg P. Rasoanaivo R. Milijaona J. Rakotoarimanga H. Rafatro B. Robijaona A. Rakoto-Ratsimamanga F. Verdier J. le Bras 《Phytotherapy research : PTR》1994,8(1):18-21
Hernandia voyronii is traditionally used as adjuvant to chloroquine in Madagascar. Neutral and basic alkaloidal extracts of this plant were evaluated for their intrinsic in vitro antimalarial activity, cytotoxicity and chloroquine potentiating action against the chloroquine resistant Plasmodium falciparum strain FCM29. Bioassay directed fractionation clearly demonstrated that both the intrinsic antimalarial activity and the chloroquine potentiating action was localized in the polar alkaloidal extract. Moreover, this extract had low cytotoxicity to HeLa cells and L929 fibroblasts. These results support the traditional use of H. voyronii as an antimalarial and adjuvant to chloroquine. 相似文献
103.
104.
Tetrandrine and related bis—benzylisoquinoline alkaloids from medicinal herbs:cardiovascular effects and mechanisms of action 总被引:10,自引:1,他引:9
Tetrandrine(TET),a bis-benzylisoquinoline alkaloid purified and identified an active ingredient in a Chinese medicinal herb,Radix Stephanae tetrandrae,has been used traditionally for the treatment of congestive circulatory disorder and inflammatory diseases.TET,together with a few of its structural analogues,has long been demonstrated to have antihypertensive action in clinical as well as animal studies.Presumably,the primary anti-hypertensive action of TET is due to its vasodilatory properties.TET prevents or inhibits vascular contraction induced by membrane depolarization with KCl or α-adrenoceptor activation with phenylephrine (PE).TET(30μmol/L) also inhibits the release of endothelium-derived nitric oxide(NO) as well as NO production by inducible NO synthase.TET apparently inhibits multiple Ca^2 entry pathways as demonstrated in cell types lacking the L-type Ca^2 channels.In cardiac muscle cells,TET inhibits both L-and T-type Ca^2 channels.In addition to its actions on cardiovascular tissues,TET may also exert its anti-hypertensive action via a Ca^2 -dependent manner on other tissues intimately involved in the modulation of blood pressure control,such as adrenal grands.In adrenal glomerulosa cells,KCl-or angiotensin II-induced aldosterone synthesis is highly dependent on extracellular Ca^2 .Steroidogenesis and Ca^2 -influx in bovine adrenal glomerulosa cells have been shown to be potently inhibited by TET.In bovine adrenal chromaffin cells,TET inhibits Ca^2 currents via L-and N-type channels as well as other unidentified channels with IC50 of 10μmol/L.Other than the Ca^2 antagonistic effects.TET also interacts with the α-adrenergic receptors and muscarinic receptors based on functional as well as radioligand binding studies.Apart from its functional effects,TET and related compounds also exert effects on tissue structures,such as remodelling of hypertrophied heart and inhibition of angiogenesis,probably by causing apoptotic responses.TET is also known for its anti-inflammatory and anti-fibrogenic actions,which make TET and related compound potentially useful in the treatment of lung silicosis,liver cirrhosis,and rheumatoid arthritis. 相似文献
105.
Immunomodulatory effects and mechanisms of plant alkaloid tetrandrine in autoimmune diseases 总被引:14,自引:0,他引:14
Lai JH 《Acta pharmacologica Sinica》2002,23(12):1093-1101
Autoimmune diseases characterized by activation of immune effector cells and damage of target organs are currently treated with a combination of several disease-modifying antirheumatic drugs (DMARDs) that preserve different immunomodulatory mechanisms. Such a combination treatment strategy not only provides synergistic effects but also reduces side effects from individual drug. Tetrandrine (Tet), purified from a creeper Stephania tetrandra S Moore, is a bis-benzylisoquinoline alkaloid and has been used to treat patients with silicosis, autoim-mune disorders, and hypertension in Mainland China for decades. The accumulated studies both in vitro and in vivo reveal that Tet preserves a wide variety of immunosuppressive effects. Importantly, the Tet-mediated immu-nosuppressive mechanisms are evidently different from some known DMARDs. The synergistic effects have also been demonstrated between Tet and other DMARDs like FK506 and cyclosporin. These results highlight Tet a very potential candidate to be consid 相似文献
106.
风湿定胶囊的质量标准研究 总被引:1,自引:0,他引:1
目的建立风湿定胶囊的质量标准。方法用中和法检测了总生物碱的限量;HPLC测定了欧前胡素的含量,色谱柱:A lltech ODS(4.0mm×250mm),流动相:甲醇-水(70∶30),检测波长248nm,结果加样回收97.74%,RSD=2.92%。线性范围为0.01564mg/mL~0.1564mg/mL,r=0.999 7,重复性RSD=1.83%(n=5),精密度RSD=0.77%(n=5)。结论方法稳定、可靠,可作为该药的质量控制方法。 相似文献
107.
Yuichi Nakamura Kaori Yomura Toshihiro Kammoto Makoto Ishimatsu Yuichi Kikuchi Kazuaki Niitsu Susumu Terabayashi Shuichi Takeda Hiroshi Sasaki Keiko Arimoto Minoru Okada Setsuko Sekita Motoyoshi Satake Yukihiro Goda 《Journal of natural medicines》2006,60(4):285-294
Aconite root has high toxicity caused by diester alkaloids, thus it was necessary to define the limiting value of diester
alkaloids used in medicine formulation. To give the quality of “Processed Aconite Root” and “Powdered Processed Aconite Root”
in the Japanese Pharmacopoeia (14th edn, supplement II), we established the official specification and evaluation methods
of standard substances. High qualitative grade diester alkaloids, aconitine, hypaconitine, jesaconitine and mesaconitine,
which were useful to evaluate the purity of processed aconite root and powdered processed aconite root, were prepared and
evaluated for their stability. We studied the physicochemical specification and evaluation methods of these alkaloids. In
addition, an “Aconitum diester alkaloids standard solution for purity”, which was used for the purity test, was prepared,
and we also studied its physicochemical specification and evaluation methods. In addition, to evaluate the quality of processed
aconite root and powdered processed aconite root, a TLC identification test was established. A monoester alkaloid of benzoylmesaconine
hydrochloride was used as the reference standard in the latter test, and we also investigated its physicochemical specification
and evaluation methods. 相似文献
108.
109.
目的考察和比较湖北黄连GAP基地选育的3个不同品系黄连(大花叶、无光叶、小花叶)的产量和质量。方法采用田间随机区组设计,连续3年采集3个品系黄连根茎样品,分别以烘干法测定其质量,用紫外分光光度法和高压液相色谱法分别测定其总生物碱和盐酸小檗碱的量。结果在考察的3个品系药材样本中,各品系三年生黄连产量没有显著差异(P>0.05),在四年生和五年生黄连中,大花叶和无光叶品系产量均明显高于小花叶品系(P<0.05);在三年生、四年生、五年生黄连中,各品系总生物碱和盐酸小檗碱的量无明显差异(P>0.05)。结论大花叶和无光叶品系的黄连产量高、质量合格,可作为黄连规范化种植的种子基原。 相似文献
110.