首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18787篇
  免费   1245篇
  国内免费   75篇
耳鼻咽喉   216篇
儿科学   419篇
妇产科学   345篇
基础医学   2613篇
口腔科学   319篇
临床医学   1621篇
内科学   4841篇
皮肤病学   416篇
神经病学   1619篇
特种医学   615篇
外科学   2665篇
综合类   238篇
一般理论   8篇
预防医学   1395篇
眼科学   412篇
药学   1113篇
中国医学   77篇
肿瘤学   1175篇
  2023年   132篇
  2022年   330篇
  2021年   545篇
  2020年   306篇
  2019年   447篇
  2018年   515篇
  2017年   342篇
  2016年   365篇
  2015年   449篇
  2014年   619篇
  2013年   840篇
  2012年   1333篇
  2011年   1351篇
  2010年   773篇
  2009年   668篇
  2008年   1129篇
  2007年   1194篇
  2006年   1175篇
  2005年   1106篇
  2004年   1009篇
  2003年   963篇
  2002年   952篇
  2001年   136篇
  2000年   123篇
  1999年   164篇
  1998年   198篇
  1997年   165篇
  1996年   166篇
  1995年   120篇
  1994年   115篇
  1993年   99篇
  1992年   101篇
  1991年   101篇
  1990年   89篇
  1989年   69篇
  1988年   79篇
  1987年   83篇
  1986年   67篇
  1985年   87篇
  1984年   97篇
  1983年   93篇
  1982年   111篇
  1981年   124篇
  1980年   107篇
  1979年   67篇
  1978年   74篇
  1977年   87篇
  1976年   64篇
  1974年   55篇
  1973年   50篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Stellate ganglion (SG) neurons provide the main sympathetic innervation to the heart and help to regulate cardiac function. The purpose of this study was to determine if ultrasound imaging could be employed to retrograde label rat SG neurons innervating the heart without employing thoracotomy. In addition, electrophysiological experiments were performed to characterize the modulation of Ca(2+) channels by neurotransmitters in unlabeled and dye-labeled SG neurons. Fluorescence imaging of actutely isolated cells revealed that dye uptake was successful within five days following injection of dye in the cardiac muscle. Whole-cell voltage-clamp recordings revealed that the majority of the Ca(2+) current was carried by N-type Ca(2+) channels. Finally, fluorescence dye uptake did not appear to affect the modulation of Ca(2+) currents following exposure of SG neurons to norepinephrine, adenosine and neurokinin A. These results demonstrate that ultrasound imaging-guided percutaneous injection can be effectively employed to retrograde label neurons innervating the heart.  相似文献   
992.
Selective serotonin reuptake inhibitors (SSRIs) are well-established medications for the treatment of mood disorders including major depression. These agents are also known to exhibit potent antiplatelet and endothelium protective effects effects. Additionally, SSRIs can exacerbate the development of inflammation, and modulate the interleukin and interferon production. All of the above suggest that SSRIs therapy could be considered as a potential strategy for the wound healing treatment. We summarized some body of the available data on the history of serotonin metabolism, mechanism of action of ketanserin, and hypothesize why SSRIs may be beneficial in the wound repair natural history. Different pathophysiological considerations are also reflected in this review. Finally, we suggest that the topical use of SSRIs may represent a promising avenue for future strategies affecting wound repair in high-risk patients, especially those with diabetes mellitus, venous insufficiency, obesity, and other vascular disorders.  相似文献   
993.
OBJECTIVE: The alpha(1A)-adrenergic receptor is highly expressed in human vasculature including resistance arteries and veins, and its stimulation is primarily responsible for adrenergically mediated smooth muscle contraction. Variability in sensitivity to phenylephrine, an alpha(1A) adrenergic agonist, has a large genetic component. We examined the hypothesis that a common polymorphism of alpha(1A)-adrenergic receptor (Arg347Cys) affects in vivo response. METHODS: We measured vascular sensitivity to phenylephrine using the dorsal hand vein linear variable differential transformer technique and determined alpha(1A)-adrenergic receptor genotype in 74 healthy, nonsmoking adults (28 Arg/Arg, 30 Arg/Cys, and 16 Cys/Cys). RESULTS: Sensitivity to phenylephrine, expressed as the dose of phenylephrine resulting in 50% venoconstriction (Phe(50)), was not significantly different in subjects with the 3 alpha(1A) adrenergic receptor genotypes: Phe(50) geometric mean (95% confidence interval) was 513 ng/min (287-918 ng/min) for Arg/Arg, 431 ng/min (274-680 ng/min) for Arg/Cys, and 471 ng/min (197-1124 ng/min) for Cys/Cys (P =.90). CONCLUSION: We conclude that the Arg347Cys receptor polymorphism does not alter agonist-mediated venoconstriction in vivo.  相似文献   
994.
In this study, we evaluated the in vitro activity of anidulafungin against selected mold isolates. Anidulafungin showed promising activity against Bipolaris spicifera, Exophiala jeanselmei, Fonsecaea pedrosoi, Madurella mycetomatis, Penicillium marneffei, Phialophora verrucosa, Pseudallescheria boydii, Sporothrix schenckii, and Wangiella dermatitidis.  相似文献   
995.
996.
997.
998.
Re-operation for hyperparathyroidism   总被引:1,自引:0,他引:1  
INTRODUCTION: Re-operation for hyperparathyroidism (HPT) represents a challenge for experienced endocrine surgeons. The present study reviews the technical and pathological factors for failure of initial surgery and identifies strategies to approach re-operative parathyroidectomy. METHODS: Clinical details, operation notes, pathology, localization studies and complications for re-operative cases performed by three surgeons were reviewed. RESULTS: Over a 10-year period there were 40 re-operative cases with a 98% success rate. There were 31 patients with primary HPT, 21 with persistent primary (PP) and 10 with recurrent primary (RP). Multigland disease (MGD) was present in 19 of the 31 (61%) primary HPT cases. The culprit gland was ectopic in 14 cases, at a normal location in 10 and there was regrowth at previously excised sites or remnant disease in 10. There were nine patients with secondary HPT, four with persistent secondary (PS) and five with recurrent secondary (RS). The culprit gland was ectopic in five, at a normal location in four and regrowth at a previously excised site in two. Pre-operative investigations were employed in all cases and the most helpful were sestamibi scan (S) and selective venous sampling (SVS) for parathyroid hormone (PTH) concentration. True positive localizations for S was in 20 of 34 cases (59%), SVS in seven of nine (78%), computed tomography (CT) in seven of 17 (41%) and ultrasound scan (USS) in 10 of 28 (36%). CONCLUSIONS: Re-operative parathyroidectomy can be performed by experienced surgeons with a very high success rate and minimal complications.  相似文献   
999.
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号