全文获取类型
收费全文 | 9062篇 |
免费 | 643篇 |
国内免费 | 221篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 100篇 |
妇产科学 | 77篇 |
基础医学 | 735篇 |
口腔科学 | 95篇 |
临床医学 | 785篇 |
内科学 | 1324篇 |
皮肤病学 | 81篇 |
神经病学 | 1174篇 |
特种医学 | 200篇 |
外科学 | 253篇 |
综合类 | 779篇 |
一般理论 | 5篇 |
预防医学 | 763篇 |
眼科学 | 35篇 |
药学 | 2823篇 |
中国医学 | 619篇 |
肿瘤学 | 54篇 |
出版年
2024年 | 14篇 |
2023年 | 116篇 |
2022年 | 124篇 |
2021年 | 248篇 |
2020年 | 261篇 |
2019年 | 342篇 |
2018年 | 353篇 |
2017年 | 376篇 |
2016年 | 319篇 |
2015年 | 234篇 |
2014年 | 388篇 |
2013年 | 1551篇 |
2012年 | 377篇 |
2011年 | 416篇 |
2010年 | 364篇 |
2009年 | 317篇 |
2008年 | 347篇 |
2007年 | 359篇 |
2006年 | 351篇 |
2005年 | 270篇 |
2004年 | 248篇 |
2003年 | 249篇 |
2002年 | 222篇 |
2001年 | 172篇 |
2000年 | 146篇 |
1999年 | 139篇 |
1998年 | 130篇 |
1997年 | 127篇 |
1996年 | 115篇 |
1995年 | 85篇 |
1994年 | 129篇 |
1993年 | 71篇 |
1992年 | 73篇 |
1991年 | 83篇 |
1990年 | 66篇 |
1989年 | 78篇 |
1988年 | 48篇 |
1987年 | 50篇 |
1986年 | 74篇 |
1985年 | 106篇 |
1984年 | 118篇 |
1983年 | 67篇 |
1982年 | 67篇 |
1981年 | 43篇 |
1980年 | 35篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1973年 | 4篇 |
排序方式: 共有9926条查询结果,搜索用时 15 毫秒
41.
Substance P and human nasal mucociliary activity 总被引:2,自引:0,他引:2
Summary Substance P (SP), a potent inflammatory agent, has been found in sensory nerve fibres in the nasal mucosa in several experimental animals as well as in man. It may participate in the inflammatory response as part of the mucosal defence against foreign materials. In experimental animals SP has been found to increase mucociliary in airway mucosa. The present study was performed in order to find out the relationship between topically applied SP and nasal mucociliary function in humans. Thirteen healthy volunteers were challenged with 65 µg SP or placebo in a randomized cross over fashion and mucociliary transport time was determined each time using the saccharine dye test. The dose of SP was chosen after an open dose-response study. No statistically significant change in the mucociliary transport time was found after challenge with SP as compared to placebo. The possible reasons for this are discussed. 相似文献
42.
In a study to elucidate molecular mechanisms in pain, substance P-like immunoreactivity (SP-LI) was measured in lumbar CSF from 75 patients with lower back pain. Two samples – one before and one after lidocaine treatment – were obtained from each patient, and total SP-LI was measured in unfractionated (no HPLC) samples. SP-LI data were separated into three categories: placebo responders, pharmacological responders, and pharmacological non-responders. A significant difference was observed between the total SP-LI measurement of first and second samples of pharmacological non-responders. Distribution of SP-LI immunoreactive molecular species in two CSF patient samples (no ODS) was analyzed with a combination of reversed phase (RP) HPLC and RIA. Immunoreactivity in collected HPLC fractions was measured at calibrated retention times of synthetic SP-sulfoxide (SP-O), SP, and SP5–11. Qualitative and quantitative differences in those HPLC-RIA metabolic profiles were observed within and between those two patients' samples. These data indicate that the type and amount of SP metabolism and SP precursor-processing differs in CSF between these two representative patients and within the short amount of time elapsed between acquiring these two samples. 相似文献
43.
44.
用改良的四氮唑硝基蓝(NBT)还原法观察了电针以及生物活性物质(BAS)包括5-羟色胺(5-HT)、血管活性肠肽(VIP)、生长抑素(SOM)和P物质(SP)对大鼠多形核白细胞(PMN)杀菌功能的影响。结果表明:电针及BAS均能增强大鼠PMN的杀菌功能(P<0.01);BAS对大鼠PMN的杀菌功能具有双向调节效应。纳洛酮可阻抑电针对PMN杀菌功能的提高(P>0.05);可被BAS所翻转。电针的镇痛效应和NBT阳性细胞提高效应之间存在着明显的正相关(P<0.01)。 相似文献
45.
C De Simone A Misefari V Covelli A B Maffione S Antonaci E Jirillo 《Journal of clinical laboratory analysis》1989,3(6):345-349
The effects of substance P (SP) on Salmonella minnesota R345 (Rb) binding to human peripheral blood lymphocytes (PBL) were evaluated. Two parameters of bacterial cytoadherence were considered, namely the binding lymphocytes (BL) and the number of bound-bacteria/lymphocyte (BB). The results showed that SP inhibits both BL and BB in a significant manner. Furthermore, distribution of Salmonella binding to CD4+ and CD8+ lymphocytes was studied following SP pretreatment of lymphoid cells. This neuropeptide is able to hamper the bacterial cytoadherence to both T-cell subpopulations and, in particular, the inhibitory effect on the T-suppressor/cytotoxic subset was more pronounced. These findings are discussed in terms of SP intervention in the mechanism of host protection against invading microorganisms. 相似文献
46.
Rat spinal dorsal horn neurons in slice preparations perfused with Ringer solution containing 0.5-1 microM TTX and/or 10-20 mM tetraethylammonium at 29 degrees C, were studied by using a single microelectrode voltage-clamp technique. Slow persistent inward currents were recorded during depolarizing voltage commands to membrane potentials positive to about -40 mV. The inward current was depressed by removing external Ca, or by adding 0.1-0.2 mM Cd, 5 mM Co or 0.1 mM verapamil, and was increased by adding Ba or Bay-K 8644. Substance P (SP) augmented a persistent slow inward Ca-sensitive current in a dose-dependent manner. It is suggested that this effect may be instrumental in generating the SP-evoked slow depolarization, increase in membrane excitability, and the 'bursting' behavior in the immature rat dorsal horn neurons. In addition, in some neurons SP reduced the M-like current, which effect may contribute to, but not explain, generation of the SP-induced slow depolarization. 相似文献
47.
动脉硬化性脑白质病的CT表现与临床分析 总被引:1,自引:0,他引:1
目的 :探讨动脉硬化性脑白质病的临床与CT表现特点。方法 :收集 10 0例动脉硬化性脑白质病的临床与CT资料进行综合分析。结果 :10 0例的CT表现为 :弥漫性脑白质低密度改变 ,主要分布在双侧脑室旁及半卵圆中心白质区 ,病灶多呈条带状及月晕状。合并脑萎缩 90例 ;脑梗塞 76例 ,其中 2 5例有大的梗塞灶 ,其余为腔隙性梗塞 ;脑出血 9例 ,其中位于壳核 5例 ,丘脑 3例 ,小脑 1例 ;有 15例伴发基底节区软化灶。增强扫描 8例 ,显示病灶无明显增强。结论 :动脉硬化性脑白质病是发生于老年人的缺血性脑血管病 ,高血压动脉硬化是其主要发病因素。 相似文献
48.
Michael F Grunebaum Hanga C Galfalvy C Matthew Nichols Nathilee A Caldeira Leo Sher Kanita Dervic Ainsley K Burke J John Mann Maria A Oquendo 《Bipolar disorders》2006,8(5P1):496-502
Objectives: The goal of this retrospective study was to examine factors differentiating persons with bipolar disorder who did or did not have comorbid lifetime substance use disorders (SUD) at an index assessment. We also explored the chronology of onset of mood and SUD.
Methods: We studied 146 subjects with DSM-defined bipolar disorder. Subgroups with and without lifetime SUD were compared on demographic and clinical measures.
Results: Substance abuse disorders in this bipolar sample were associated with male sex, impulsive-aggressive traits, comorbid conduct and Cluster B personality disorders, number of suicide attempts and earlier age at onset of a first mood episode. In a multivariable logistic regression analysis, male sex and aggression and possibly earlier age at mood disorder onset were associated with SUD. In those with or without SUD, the first mood episode tended to be depressive and to precede the onset of SUD.
Conclusions: In persons with bipolar disorder, an earlier age of onset and aggressive traits appear to be factors associated with later development of comorbid SUD. 相似文献
Methods: We studied 146 subjects with DSM-defined bipolar disorder. Subgroups with and without lifetime SUD were compared on demographic and clinical measures.
Results: Substance abuse disorders in this bipolar sample were associated with male sex, impulsive-aggressive traits, comorbid conduct and Cluster B personality disorders, number of suicide attempts and earlier age at onset of a first mood episode. In a multivariable logistic regression analysis, male sex and aggression and possibly earlier age at mood disorder onset were associated with SUD. In those with or without SUD, the first mood episode tended to be depressive and to precede the onset of SUD.
Conclusions: In persons with bipolar disorder, an earlier age of onset and aggressive traits appear to be factors associated with later development of comorbid SUD. 相似文献
49.
旋毛虫幼虫分泌物抗原在小鼠体内诱生肿瘤细胞毒因子的研究 总被引:6,自引:0,他引:6
本文应用L929细胞杀伤法,对注射旋毛虫肌肉期幼虫分泌物(L1ES)的小鼠血清进行了检测,发现L1ES对已注射卡介苗(BCG)或感染旋毛虫的小鼠,均能诱生肿瘤细胞毒因子(TCF),而正常对照鼠则不能发生,表明L1ES诱生TCF需要首先激活巨噬细胞(Mφ)这一基本条件。将L1ES置37℃、1h,56℃、30min或100℃、2min处理后,其诱生TCF的能力均明显高于对照组(P<0.05)。L1ES 相似文献
50.
大鼠延髓腹侧面头端应用毒扁豆碱引起血压升高和心率加快,伴有延髓腹侧面头端胆碱酯酶活性降低和脊髓蛛网膜下腔灌流液中P物质样免疫反应活性升高。在延髓腹侧面头端应用阿托品或脊髓蛛网膜下腔注射P物质拮抗剂D-脯~2,D-苯丙~7,D-色~9-P物质均可阻断毒扁豆碱的心血管效应。脊髓蛛网膜下腔注射P物质抗血清或辣椒素均可减弱毒扁豆碱的升压反应。实验结果提示,毒扁豆碱作用于延髓腹侧面头端的M受体,兴奋了延髓-脊髓P物质能神经元下行通路,使之释放P物质,引起交感肾上腺髓质系统兴奋,从而使血压升高和心率加快。 相似文献