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   164927篇
  免费   14520篇
  国内免费   9140篇
耳鼻咽喉   1413篇
儿科学   2403篇
妇产科学   3434篇
基础医学   17942篇
口腔科学   3319篇
临床医学   20444篇
内科学   25997篇
皮肤病学   1905篇
神经病学   8544篇
特种医学   5444篇
外国民族医学   59篇
外科学   17294篇
综合类   24847篇
现状与发展   32篇
一般理论   21篇
预防医学   11526篇
眼科学   4324篇
药学   17187篇
  128篇
中国医学   8320篇
肿瘤学   14004篇
  2024年   443篇
  2023年   2228篇
  2022年   5230篇
  2021年   6973篇
  2020年   5315篇
  2019年   4805篇
  2018年   5106篇
  2017年   4787篇
  2016年   4347篇
  2015年   6835篇
  2014年   8636篇
  2013年   8610篇
  2012年   12774篇
  2011年   13669篇
  2010年   9188篇
  2009年   7530篇
  2008年   9697篇
  2007年   9703篇
  2006年   9121篇
  2005年   8580篇
  2004年   6132篇
  2003年   5622篇
  2002年   4674篇
  2001年   3926篇
  2000年   3812篇
  1999年   3681篇
  1998年   1910篇
  1997年   1890篇
  1996年   1472篇
  1995年   1412篇
  1994年   1301篇
  1993年   794篇
  1992年   1196篇
  1991年   1102篇
  1990年   940篇
  1989年   812篇
  1988年   732篇
  1987年   655篇
  1986年   531篇
  1985年   419篇
  1984年   284篇
  1983年   244篇
  1982年   126篇
  1981年   135篇
  1980年   95篇
  1979年   172篇
  1978年   136篇
  1977年   102篇
  1974年   101篇
  1972年   91篇
排序方式: 共有10000条查询结果,搜索用时 13 毫秒
31.
32.
目的 探索对海洛因依赖重度药瘾较理想的戒毒治疗方法。  方法 采用美沙酮与丁丙诺啡联合用药方案 ,对海洛因依赖重度药瘾 41例行戒毒治疗 ,1 2天为一疗程 ,并与单用美沙酮组 2 0例进行比较。  结果 联合用药组控制症状较彻底 ,鸦片类药物戒断症状量表 (OWS)总分平稳下降 ,症状波动小 ,减药顺利 ,两药替换平稳 ,戒毒成功率 73 2 %。  结论 我们认为美沙酮联用丁丙诺啡是一种值得推荐的戒毒治疗方法。  相似文献   
33.
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996  相似文献   
34.
MK-679 (R(?)-3-((3-(2-(7-chloro-2-quinolinyl)ethenyl)phenyl)(3-(dimethylamino)-3-oxopropyl)thio)methyl)thio(propanoic acid) is a potent and specific LTD4-receptor antagonist. The disposition of MK-679 was investigated in a three-way crossover study in 12 healthy males receiving single intravenous doses of 75, 250, and 500 mg of MK-679. A greater than proportional increase in the area under the plasma concentration—time curve of MK-679 was observed with increase in dose. The plasma concentration data for each subject fitted well to the differential equations for a two-compartment model with linear tissue distribution and Michaelis-Menten elimination from the central compartment, indicating that the elimination of MK-679 in humans is saturable. In a previous study, the disposition of MK-679 in humans was also dose-dependent when given together with its S(+)-isomer, L-668,018. Thus, the disposition of MK-679 in humans is dose-dependent regardless of the presence of its stereoisomer. Also, the bioavailability of MK-679 was determined in six healthy males receiving simultaneously an oral dose of 250 mg of MK-679 and intravenous infusion of 1 mg 14C-MK-679. Results of this study indicate that the oral bioavailability of MK-679 is nearly quantitative.  相似文献   
35.
Clinically significant contact lens induced corneal warpage is seen in a small proportion of soft and rigid contact lens wearers. Previous studies using the keratometer have found no correlation between the fit of the lens and the induced topographic changes. In this study, using computer-assisted topographic analysis, seven eyes (four patients) with rigid contact lens-induced corneal warpage were noted to have topographic abnormalities that correlated with the decentered resting position of the contact lens on the cornea. The warpage topography for each of these corneas was characterized by a relative flattening of the cornea underlying the resting position of the contact lens. Lenses that rode high, for example, produced flattening superiorly and resulted in a relatively steeper contour inferiorly that simulated the topography of early keratoconus patients who had not worn contact lenses. After discontinuing contact lenses the corneal topography returned to a normal pattern in five eyes. Two eyes retained asymmetry that is not characteristic of normal corneas. Up to 6 months was required for the corneas to return to a stable topography after contact lens wear was discontinued.  相似文献   
36.
37.
Elevation of prostaglandins and protein in the aqueous humor is an immediate response to Yag-laser anterior capsulotomy. There was a significant correlation between prostaglandins and thromboxane to the elevation of intraocular pressure. The elevation of protein concentration was proportional to the elevation of prostaglandin F1, but not to thromboxane. The biochemical changes in the aqueous humor were more severe as laser power was increased above 3 mj. While the role of prostaglandins in the elevation of intraocular pressure is uncertain, the present data recommend the selection of laser power below 3 mj to avoid pressure rise instead of inhibition of all prostaglandin synthesis by medication.  相似文献   
38.
We report a case of calcified chronic encapsulated intracerebral haematoma (ICH) in a 29-year-old female who presented with progressive left sided weakness and intermittent seizures since childhood. The preoperative magnetic resonance (MR) imaging of the head initially suggested that a partially thrombosed aneurysm or vascular malformation was present. However, no vascular stain was found on the digital subtraction angiography (DSA) of both the carotid and vertebral arteries. The excised mass was histologically diagnosed as a chronic ICH. We traced the patient's medical history and found that at the age of one she sustained a head injury after a fall. So far, to our knowledge, no case of epilepsy secondary to a calcified chronic encapsulated ICH occurring 28 years after head injury has been reported. Calcified chronic encapsulated ICH concomitant with new bone formation within is even rarer. The possible pathogenesis of this case is discussed.  相似文献   
39.
本文作者比较了不同时期的纸质病案的使用率,讨论了旧病案的缺点,如难于保存,占用空间及实用价值不大.作者提出了改进保存病案的办法.  相似文献   
40.
Since the beginning of this century, trans- naso-sphenoidal resection of the pituitary fossa tumors has been widely used clinically. It has more merits than other operative approaches used before. In China it has been adopted by both ENT doctors and neurosurgeons since 1959.1 In order to afford some relevant anatomical data, we measured 137 adult sagittal plane skulls with distinct landmarks.  相似文献   
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