全文获取类型
收费全文 | 55369篇 |
免费 | 4968篇 |
国内免费 | 3131篇 |
专业分类
耳鼻咽喉 | 854篇 |
儿科学 | 683篇 |
妇产科学 | 616篇 |
基础医学 | 7453篇 |
口腔科学 | 1062篇 |
临床医学 | 6602篇 |
内科学 | 9235篇 |
皮肤病学 | 811篇 |
神经病学 | 3303篇 |
特种医学 | 2730篇 |
外国民族医学 | 21篇 |
外科学 | 6036篇 |
综合类 | 6270篇 |
现状与发展 | 13篇 |
一般理论 | 5篇 |
预防医学 | 3222篇 |
眼科学 | 1307篇 |
药学 | 5618篇 |
38篇 | |
中国医学 | 2450篇 |
肿瘤学 | 5139篇 |
出版年
2024年 | 175篇 |
2023年 | 875篇 |
2022年 | 2157篇 |
2021年 | 3034篇 |
2020年 | 2195篇 |
2019年 | 2016篇 |
2018年 | 2051篇 |
2017年 | 1836篇 |
2016年 | 1837篇 |
2015年 | 2662篇 |
2014年 | 3086篇 |
2013年 | 2992篇 |
2012年 | 4291篇 |
2011年 | 4539篇 |
2010年 | 2805篇 |
2009年 | 2240篇 |
2008年 | 2969篇 |
2007年 | 2895篇 |
2006年 | 2708篇 |
2005年 | 2552篇 |
2004年 | 1879篇 |
2003年 | 1719篇 |
2002年 | 1438篇 |
2001年 | 1138篇 |
2000年 | 1123篇 |
1999年 | 1149篇 |
1998年 | 624篇 |
1997年 | 603篇 |
1996年 | 473篇 |
1995年 | 428篇 |
1994年 | 382篇 |
1993年 | 220篇 |
1992年 | 372篇 |
1991年 | 287篇 |
1990年 | 276篇 |
1989年 | 247篇 |
1988年 | 221篇 |
1987年 | 193篇 |
1986年 | 161篇 |
1985年 | 121篇 |
1984年 | 81篇 |
1983年 | 67篇 |
1982年 | 26篇 |
1981年 | 35篇 |
1980年 | 22篇 |
1979年 | 37篇 |
1978年 | 21篇 |
1977年 | 22篇 |
1976年 | 32篇 |
1974年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Effects of sodium salts of various monovalent inorganic anions on transdermal permeation of salicylic acid were investigated. In in-vitro experiment using a Franz-type diffusion cell and excised mouse skin, the permeation-enhancing activities of the sodium salts of inorganic anions were roughly proportional to lyotropic Hofmeister swelling abilities of the anions; F?<SO4 2?<Cl? <ClO4 ?<NO3 <SCN? <Br <I?, i.e. l, Br and SCN increased the flux of drugs through the mouse skin, while F?, SO4 2?, Cl?, ClO4 ? and NO3 ? decreased or did not affect the flux. In invivo experiment using the rabbit as the test animal, the plasma concentration of salicylic acid of the rabbit to which 10%-salicylic acid ointment containing 5%-Nal or NaBr was applied was significantly higher than that of the rabbit to which the ointment without the electrolytes was applied. The amounts of sterol leached out of stratum corneum sheet when the sheet was immersed in aqueous solutions of Nal, NaBr, or NaSCN were much more than that of stratum corneum immersed in aqueous solutions of the other inorganic anions. The FTIR/ATR spectroscopy showed that the peaks at 2853 cm?1 and 2924 cm?1 in the IR absorption spectrum of the stratum corneum sheet of the mouse were shifted to higher frequencies by the anions which enhanced the transdermal drug permeation, while not shifted by the anions which did not have any permeation-enhancing activities or have permeation-reducing activities. These results suggest that sodium salts of some anions such as iodide, bromide and thiocyanate enhance transdermal permeation of salicylic acid through swelling and perturbation of the skin structure by these anions. 相似文献
32.
选择分别位于bcr/abl嵌合基因的Mbcrl第二外显子和abl的第二外显子上的两条引物,对18例慢粒白血病及2例急淋白血病标本进行逆转录PCR(RT-PCR)检测。结果:在18例包括ph(+)和ph(-)不同病期的慢粒白血病患者血中均检出bcr/abl嵌合基因的表达,其中14例为K-28型表达,1例为L-6型表达,3例为K-28型,L-6型同时表达;2例急淋白血病标本中1例为K-28型表达。研究结果表明,1.bcr/abl嵌合基因是慢粒白血病的一个重要分子生物学特征;2.ph(+)和ph(-)慢粒白血病的分子生物学基础相同,即均有bcr/abl嵌合基因;3.至少部分急淋白血病与慢粒白血病有相同的分子生物学基础;4.bcr的断裂点位置可能有一定的临床意义,但有待进一步研究;5.同时表达L-6型和K-28型的情况多见于急变区,此现象提示体内可能同时有两类不同嵌合的白血病细胞或白血病急变期bcr出现新的重排。 相似文献
33.
Subtypes of alpha 1-adrenoceptors in rat blood vessels 总被引:13,自引:0,他引:13
Two alpha 1-adrenoceptor subtypes (alpha 1A and alpha 1B) have been distinguished by competitive antagonists and the alkylating agent chloroethylclonidine. The chloroethylclonidine-insensitive subtype (alpha 1A) has been suggested to selectively activate Ca2+ influx through dihydropyridine-sensitive channels in smooth muscle. We compared the effects of chloroethylclonidine and nifedipine on contractile responses to norepinephrine (NE) in rat blood vessels. Pretreatment with chloroethylclonidine caused a large shift to the right and decrease in maximum for NE-induced contractions of rat aorta, however, nifedipine had no effect in this tissue. Chloroethylclonidine had no effect on NE-induced contractions of rat renal arteries, which were almost completely abolished by nifedipine. Both chloroethylclonidine and nifedipine partially attenuated NE-induced contractions in rat mesenteric artery and portal vein. Addition of nifedipine abolished residual contractions remaining after chloroethylclonidine pretreatment in all four types of vessels. The pA2 for the competitive antagonist WB 4101 was highest in renal artery and lowest in aorta. These results suggest that the sensitivity of rat blood vessels to chloroethylclonidine is inversely related to their sensitivity to nifedipine, and support the existence of two alpha 1-adrenoceptor subtypes in rat blood vessels. Rat aorta appears to contain primarily alpha 1B receptors, renal artery primarily alpha 1A, and mesenteric artery and portal vein mixtures alpha 1A of and alpha 1B. 相似文献
34.
本文介绍了鼻内法鼻泪管逆行切除术的切除器制备、应用器械、手术方法及术后处理。并应用本法治疗慢性泪囊炎106例113眼,术后随访1 ̄5年,痊愈93.8%,无效6.2%。 相似文献
35.
36.
Li-xin Yu Jun-sheng Ye Jian Xu Wen-feng Deng Cong-xiang Han Gui-rong Ye Shao-jie Fu Chuan-fu Du Jun-jie Ma Yi-bin Wang Xiao-you Liu Chuan-jiang Li 《第一军医大学学报》2003,23(12):1332-3, 1337
OBJECTIVE: To study the effect of combined transplantation of the liver and the pancreas in diabetic patients with end-stage liver disease, and explore the optimal surgical procedure. METHODS: Simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantations were performed in a patient diagnosed as having chronic hepatitis B, hepatocirrhosis, hepatic cellular cancer, and insulin-dependent diabetes. Immunosuppression therapy utilized prednisone, tacrolimus (FK506), mycophenolate mofetil (MMF), and simulect. The function of the liver graft, serum amylase and lipase, blood glucose, and C-peptide were monitored after transplantation. RESULTS: Insulin was withdrawn at the 6th day after operation, good liver allograft functional recovery was achieved, without such complications as pancreatitis, thrombosis, and localized infections. CONCLUSION: End-stage liver disease with concomitant insulin-dependent diabetes is the indication for combined liver-pancreas transplantations, for which simultaneous orthotopic liver and heterotopic pancreas-duodenum transplantations may constitute the optimal surgical approaches as the primary choice. 相似文献
37.
38.
39.
YOU Han XIAO Bing CUI Da-Xiang SHI Yong-Quan FAN Dai-Ming 《World journal of gastroenterology : WJG》1998,4(4)
AIM To clone novel gastric cancer-associated genes and investigate their roles in gastric cancer occurrence.METHODS A method called differential display was used which allows the identification of differentially expressed genes by using PAGE to display PCR-amplified cDNA fragments between gastric cancer cells and normal gastric mucosa cells. These fragments were cloned into plasmid vector pUC18. Homology analysis was made after sequencing these fragments.RESULTS Two novel genes were identified compared with sequences from GenBank. One was registered with the AD number AF 051783. In situ hybridization showed that these two novel genes expressed specifically in gastric cancer tissues.CONCLUSION The two novel genes obtained by differential display were confirmed to be gastric cancer-associated genes using in situ hybridization. 相似文献
40.
我国环卫设备的现状与发展趋势——环卫设备的标准化、系列化 总被引:1,自引:0,他引:1
介绍了我国环卫设备的发展现状,并提出了存在的一些问题.根据我国环卫产业政策的有关要求:论述了各种环卫设备研究和开发的方向,指出大力推进环卫机械设备的标准化、系列化、通用化、规模化是社会主义市场经济发展和环卫业发展的需要. 相似文献