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   129416篇
  免费   11431篇
  国内免费   6646篇
耳鼻咽喉   1228篇
儿科学   1964篇
妇产科学   2934篇
基础医学   13504篇
口腔科学   2678篇
临床医学   16001篇
内科学   20202篇
皮肤病学   1594篇
神经病学   6422篇
特种医学   4203篇
外国民族医学   40篇
外科学   13408篇
综合类   19468篇
现状与发展   20篇
一般理论   18篇
预防医学   9462篇
眼科学   3465篇
药学   13496篇
  115篇
中国医学   6792篇
肿瘤学   10479篇
  2024年   594篇
  2023年   1757篇
  2022年   4053篇
  2021年   5484篇
  2020年   4155篇
  2019年   3738篇
  2018年   3968篇
  2017年   3745篇
  2016年   3343篇
  2015年   5264篇
  2014年   6751篇
  2013年   6974篇
  2012年   10150篇
  2011年   10890篇
  2010年   7491篇
  2009年   6160篇
  2008年   7791篇
  2007年   7727篇
  2006年   7320篇
  2005年   6695篇
  2004年   4844篇
  2003年   4404篇
  2002年   3650篇
  2001年   3090篇
  2000年   2848篇
  1999年   2642篇
  1998年   1312篇
  1997年   1221篇
  1996年   986篇
  1995年   950篇
  1994年   885篇
  1993年   504篇
  1992年   889篇
  1991年   801篇
  1990年   668篇
  1989年   569篇
  1988年   525篇
  1987年   450篇
  1986年   357篇
  1985年   284篇
  1984年   184篇
  1983年   167篇
  1982年   95篇
  1981年   93篇
  1979年   140篇
  1978年   111篇
  1977年   83篇
  1974年   94篇
  1973年   72篇
  1972年   87篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
A patient with skeletal Class III malocclusion was treated in 2 phases during the early permanent dentition. In phase 1, maxillary protraction was combined with rapid palatal expansion; in phase 2, fixed appliances were placed. The results were good posttreatment, and, 1 year later, a favorable growth tendency could be observed. This report shows that treatment for a patient with skeletal Class III malocclusion can be started in the early permanent dentition, with very good final results.  相似文献   
23.
Although many monoclonal antibodies have been made in human colon cancer, none of them are from the Chinese species. Recently, a colon cancer cell line CC-M2 established from a Chinese patient has been completely characterized and used as immunogen to produce monoclonal antibodies. Monoclonal antibodies were produced by standard hybridoma technique. The fusion rate was 95.8%. An isotype IgG1 of high proliferation named as Sam-2 was used in this study. The titers were measured around 10(4). Further studies on MoAb Sam-2 through indirect immunofluorescent and immunoperoxidase tests revealed its good specificity and sensitivity in colorectal cancer tissue. In CEA study, the result indicated that Sam-2 may react on a non-CEA related antigen. For further clinical application, the antigen was identified as a glycoprotein by chemical resistant test. In preliminary studies using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting techniques, Sam-2 could recognize two closed antigens or a dimer antigen with molecular weight 25.2 and 27 Kd respectively.  相似文献   
24.
A high incidence of bladder cancer has been documented in an area of chronic arsenic (As) exposure. This study investigates the characteristics of As-associated (n = 49) and other (n = 64) bladder cancers. A higher histological grading was observed for the As-exposed tumours (P = 0.04), but no other difference in pathobiological features or prognosis was found between the two groups.  相似文献   
25.
26.
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   
27.
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   
28.
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   
29.
30.
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   
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