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   7246篇
  免费   379篇
  国内免费   58篇
耳鼻咽喉   45篇
儿科学   158篇
妇产科学   38篇
基础医学   794篇
口腔科学   157篇
临床医学   480篇
内科学   2007篇
皮肤病学   77篇
神经病学   617篇
特种医学   400篇
外科学   1159篇
综合类   60篇
预防医学   192篇
眼科学   227篇
药学   474篇
中国医学   11篇
肿瘤学   787篇
  2023年   63篇
  2022年   172篇
  2021年   261篇
  2020年   110篇
  2019年   170篇
  2018年   217篇
  2017年   187篇
  2016年   218篇
  2015年   204篇
  2014年   249篇
  2013年   307篇
  2012年   494篇
  2011年   576篇
  2010年   303篇
  2009年   252篇
  2008年   449篇
  2007年   453篇
  2006年   436篇
  2005年   406篇
  2004年   361篇
  2003年   361篇
  2002年   366篇
  2001年   128篇
  2000年   92篇
  1999年   106篇
  1998年   60篇
  1997年   56篇
  1996年   51篇
  1995年   34篇
  1994年   40篇
  1993年   26篇
  1992年   54篇
  1991年   47篇
  1990年   42篇
  1989年   36篇
  1988年   33篇
  1987年   21篇
  1986年   30篇
  1985年   42篇
  1984年   27篇
  1983年   23篇
  1982年   8篇
  1981年   10篇
  1980年   12篇
  1979年   7篇
  1978年   12篇
  1974年   8篇
  1971年   6篇
  1970年   7篇
  1968年   7篇
排序方式: 共有7683条查询结果,搜索用时 31 毫秒
1.
2.
Sentinel lymph node biopsy (SLNB) is a widely accepted standard procedure for patients with clinically localized melanoma. Melanoma prevalence and Clark's subtype differ between Asians and Caucasians. Here, we evaluated our experience on SLNB for cutaneous melanoma in a Japanese population. SLNB was performed for patients with melanoma between July 2000 and June 2014. We retrospectively analyzed 102 patients regarding association of clinicopathological features with sentinel lymph node (SLN) status, melanoma‐specific survival (MSS) and disease‐free survival (DFS). A positive SLN was significantly associated with primary Breslow thickness. Compared with 43 patients with negative SLN, 59 patients with positive SLN had significantly shorter MSS (5‐year survival rate, 94.3% vs 63.2%; = 0.0002) and DFS (5‐year survival rate, 92.7% vs 63.4%; = 0.0004). According to our subgroup analyses, nine patients with positive non‐SLN had significantly shorter MSS compared with 32 patients with negative non‐SLN (5‐year survival rate, 32.4% vs 68.5%; = 0.0273). The survival of 51 Japanese patients with acral lentiginous melanoma (ALM) was not inferior to the survival of patients with other Clark's subtype. Breslow thickness is an important factor for both MSS and DFS, and the status of SLN is the most predictive prognostic factor in Japanese patients with clinically localized melanomas, as in case of Caucasians. Features of ALM may be different between Asians and Caucasians.  相似文献   
3.
4.
High blood pressure (BP) is a major determinant of cardiovascular events in obesity. The beta2- and beta3-adrenoceptor polymorphisms are associated with obesity and hypertension. In the present study, we examine the relationships of beta2- and beta3-adrenoceptor polymorphisms with further weight gain-induced BP elevation in obese subjects. Changes in BP, body weight, total body fat-mass, waist-to-hip ratio, plasma norepinephrine (NE) and leptin levels, and beta2(Arg16Gly)- and beta3(Trp64Arg)-adrenoceptor polymorphisms were measured periodically over a 5-year period in 55 entry obese (body mass index [BMI]> or =25.0 kg/m(2)) normotensive (BP<140/90 mmHg) men. BP elevation and weight gain were defined as > or =10% increases from entry levels over 5 years in mean BP or BMI. Obese subjects with weight gain, BP elevation or weight gain-induced BP elevation had higher frequencies of the Gly16 allele of Arg16GIy and Arg64 allele of Trp64Arg. Subjects carrying the Gly16 or Arg64 alleles had significantly greater total fat-mass and waist-to-hip ratio at entry and over a 5-year period compared to the subjects who did not carry these polymorphisms. Subjects carrying the Gly16 allele had similar levels of plasma NE, higher levels of plasma leptin and a lower slope of the regression lines between plasma leptin and NE levels. Those carrying the Arg64 allele had higher plasma NE levels at entry and over a 5-year period compared to the subjects without the Arg64 allele, but plasma leptin levels and slopes were similar. The findings demonstrate that the Arg64 allele of the beta3-adrenoceptor polymorphisms relates to weight gain-induced BP elevation accompanying high plasma NE (heightened sympathetic activity) in obese men. The Gly16 allele of the beta2-adrenoceptor polymorphisms links to weight gain-induced BP elevation associated with leptin resistance. beta2- and beta3-adrenoceptor polymorphisms could predict the future BP elevation and further weight gain-induced BP elevation in originally obese subjects.  相似文献   
5.
R Kaji  A J Sumner 《Neurology》1987,37(3):410-418
Generators of median short-latency somatosensory evoked potentials were studied with three orthodiagonal pairs of bipolar electrodes. N11 was attributed to the dorsal root and dorsal column volleys. N13 had at least two subcomponents, generator dipoles of which are directed horizontally (N13a) and axially (N13b). N13a was generated in the lower cervical cord. N13b (bipolar) and P14 far-field (noncephalic reference) appeared to originate in the cuneate nucleus or spinocerebellar tracts as well as in the medial lemniscus. Bipolar recordings were useful in localizing cervical cord lesions, which was impossible in conventional monopolar recordings.  相似文献   
6.
Post-thoracotomy wound pain in 11 patients who underwent thoracic operation was controlled by intercostal nerve block with alcohol and thoracic epidural anesthesia. The intercostal nerve block was performed just before the closure of the thoracotomy wound. Epidural anesthesia was employed from the 1st to 5th post operative day. This method alleviated post-thoracotomy pain and obviated postoperative pulmonary complication in all patients in early post operative periods. In late post operative periods after discharge, intercostal nerve block could maintain excellent analgesia in 9 of 11 patients, only 2 patients required analgesic drugs or re-block of the intercostal nerve. Thus, intercostal nerve block with alcohol is an effective and simple option to control recalcitrant post-thoracotomy wound pain in thoracic surgery.  相似文献   
7.
Humoral hypercalcemia of malignancy (HHM) in neoplastic syndrome has been most commonly reported in squamous cell carcinoma. Gallbladder carcinoma with HHM is uncommon. In this report, we describe a male case of gallbladder carcinoma with marked hypercalcemia and a high level of serum parathyroid hormone-related peptide (PTHrP). An immunohistochemical examination using PTHrP was also positive.  相似文献   
8.
The midportion of the anterior cruciate ligament (ACL) of rabbits was partially transected, and the effect of hyaluronan (HA) on its healing was determined. A 1% solution of HA (HA group) or physiological phosphate-buffered saline (control group) was administered intraarticularly, at 0.1 ml/kg body weight, once a week from 1 week after the operation. Two, 4, and 6 weeks after the initiation of HA administration, the ACLs were examined grossly, histologically and immunohistochemically. At 2 weeks, the lacerated portions were completely covered with scar-like tissue in both groups. These tissue areas were smaller in the HA group than in the control group. Histologically in the HA group, the regularity of collagen fibers (indicating the maturity of regenerated collagen fibers) had increased compared to findings in the control group, and the number of fibroblastic cells decreased gradually at a significantly faster rate. The number of inflammatory cells and blood vessels decreased gradually in both groups, with these values being lower in the HA group at each time point but not significantly so. Immunohistochemical examination of the repaired tissue revealed strong staining with anti-chondroitin sulfate proteoglycan antibody in the HA group 2 weeks after the first HA administration. The staining gradually became reduced, with the rate of reduction being faster in the HA group than in the control group. The stimulation of chondroitin sulfate proteoglycan production and the faster reduction of it in the HA group suggests that HA facilitated tissue repair and inhibited the formation of scar tissue.  相似文献   
9.
The divalent cation zinc has been reported to possess several physiological properties such as blocking apoptotic cell death through an inhibitory effect on Ca2+-Mg2+ endonuclease activity, or modulating the neurotoxicity via glutamate receptor subtypes. In the present study, we investigated the effect of peripherally injected zinc on delayed neuronal death seen in the hippocampus after transient global ischemia, in order to elucidate a possible beneficial role on zinc in ischemic neuronal cell death. Forty-five adult Mongolian gerbils of both sexes underwent transient bilateral clipping of the common carotid arteries for 3 min. In the pretreated animals, ZnCl2 (20 mg/kg) was injected subcutaneously once, 1 h before ischemia (superacute group; n=6) or twice at 24 and 48 h before ischemia (subacute group; n=14). Histological survey was carried out 3 days later by in situ DNA fragmentation method and 4 days later by hematoxylin-eosin staining by semiquantatively counting dead neurons in the CA1 sector. Subacute zinc pre-administration significantly reduced the nuclear damage and subsequent neuronal death; however, superacutely pre-administered zinc did not protect hippocampal neurons against ischemia but it did not aggravate the effect of ischemia, either. The present study suggested that transfer of exogenous zinc into the intracellular space is required for neuroprotection, presumably via the anti-endonuclease activity.  相似文献   
10.
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