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   35857篇
  免费   1929篇
  国内免费   108篇
耳鼻咽喉   438篇
儿科学   2127篇
妇产科学   704篇
基础医学   4579篇
口腔科学   810篇
临床医学   2515篇
内科学   7284篇
皮肤病学   836篇
神经病学   1898篇
特种医学   798篇
外科学   4955篇
综合类   1324篇
一般理论   15篇
预防医学   2101篇
眼科学   1541篇
药学   3494篇
中国医学   274篇
肿瘤学   2201篇
  2023年   236篇
  2022年   668篇
  2021年   1156篇
  2020年   636篇
  2019年   855篇
  2018年   1046篇
  2017年   721篇
  2016年   953篇
  2015年   990篇
  2014年   1347篇
  2013年   1746篇
  2012年   2406篇
  2011年   2425篇
  2010年   1374篇
  2009年   1232篇
  2008年   1764篇
  2007年   1735篇
  2006年   1755篇
  2005年   1378篇
  2004年   1382篇
  2003年   1175篇
  2002年   1001篇
  2001年   822篇
  2000年   867篇
  1999年   729篇
  1998年   309篇
  1997年   213篇
  1996年   222篇
  1995年   217篇
  1994年   176篇
  1993年   150篇
  1992年   498篇
  1991年   404篇
  1990年   430篇
  1989年   395篇
  1988年   357篇
  1987年   356篇
  1986年   348篇
  1985年   323篇
  1984年   262篇
  1983年   219篇
  1979年   230篇
  1978年   148篇
  1977年   180篇
  1976年   139篇
  1975年   171篇
  1974年   182篇
  1973年   182篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Maximal oxygen consumption (VO2max) and maximal workload attained (WLmax) were determined in 28 Malaysian dragon boat rowers who were exercised to exhaustion on an arm ergometer. Mean VO2max was 2.75 l min-1 at a mean WLmax of 195.5 W. Anaerobic endurance power of the arms, determined by cranking at 100 RPM at a workload of 400 W and the time taken to maintain the cadence until it fell to 75 RPM, was 34.9(+/- 2.3) s. Leg performance, as determined by standing long jump and vertical jump, was 140.0(+/- 4.5) kg m and 100.3(+/- 3.1) kg m s-1 respectively. Right hand grip strength was significantly (p < 0.001) greater than the left hand. Percentage body fat of the rowers was 11.8(+/- 0.6)%. These values represent the first measurements of their kind performed on dragon boat rowers in Malaysia.  相似文献   
22.
The pulmonary intravascular macrophages (PIMs) have been described in several species of animals. This study demonstrates for the first time that the equine lung has PIMs as resident phagocytes in its microvasculature. Their salient features such as globular surface coat, structures of the endocytic pathway, and related cell organelles closely resemble those of the calf, goat, and sheep. The exquisite organization of the coat globules in the form of a linear chain was structurally similar to the lipolytic lipase and the heparin-sensitive globular coat from PIMs of calf, goat, and sheep. Monastral blue (MB) when employed as a tracer to assess the phagocytic properties of equine PIMs induced similar modification of the globules of the coat into lipid droplets, reminiscent of neutral lipids. Lipids droplets (modified coat globules) were delivered into acid phosphatase-positive endosomes and lysosomes. Concurrently, the unaltered globules of the coat, probably internalized via fluid-phase constitutive pinocytoses, followed a different endocytic pathway. Large-scale platelet uptake by the PIMs was observed with thrombocytopenia in MB-treated ponies. The possible significance of hypothetical LDL-coat and the endocytic organelles as equivalents of synthetic apparatus of vasoactive lipids in the PIMs of horse needs to be assessed in future studies.  相似文献   
23.
24.
Background: Tibialis posterior is a frequent cause of an acquired flatfoot deformity and the prevalence is not known. If tibialis posterior dysfunction was found to occur frequently, a greater awareness may result leading to earlier patient diagnosis, referral and treatment.Objectives: To validate a screening questionnaire for tibialis posterior dysfunction, and to investigate the prevalence of tibialis posterior dysfunction in a high-risk patient population.Methods: The screening questionnaire was given prospectively to 65 patients (44 females, 21 males; mean age 79.6 years) attending an unrelated care of the elderly appointment. A foot and ankle surgery fellow separately examined all feet for tibialis posterior dysfunction.Results: The survey was 100% sensitive and 98.3 % specific at detecting tibialis posterior dysfunction. Six of the 65 patients (5 females, 1 male) had tibialis posterior dysfunction, and two had bilateral involvement. All six of the patients had longstanding symptoms, all had consulted their doctor and three had seen an orthopaedic surgeon; only one of the six patients had been correctly diagnosed.Conclusions: This study suggests that tibialis posterior dysfunction occurs frequently, but is seldom diagnosed in elderly women. Further epidemiologic studies are needed to determine the true prevalence.  相似文献   
25.
26.
Thyroid function tests were performed on 16 clinically euthyroid patients with end-stage renal failure undergoing regular haemodialysis or continuous ambulatory peritoneal dialysis and compared with 8 healthy subjects. The patient groups were carefully matched, especially regarding relative duration of dialysis (mean of 24 months). Total serum thyroxine, total triiodothyronine, free thyroxine, free triiodothyronine and reverse triiodothyronine were significantly lower in both patient groups than control. The thyrothrophin response to the standard thyrotrophin-releasing hormone test was delayed and blunted. Using a novel concentration technique we measured loss of T4 in peritoneal dialysate effluent and found it to be approximately 10% of daily thyroidal T4 release.  相似文献   
27.
28.
29.
A case of organophosphate (OP) poisoning who recovered after requiring almost 1000 mg of atropine, 10 gm of PAM and ventilatory support for 7 days is presented here. The overview of organophosphate poisoning and its management is given. With the approach adopted, the mortality reported in the general medicine unit in the central hospital in Nepal is 7.4%. The two important aspects of the management are vigilance of the atropine drip, especially at night, and other physical and psychological support care of the patients.  相似文献   
30.
Exposure to air pollution affects pulmonary functions adversely. Effect of exposure to pollution on diurnal variation of peak flow was assessed in healthy students. Three hundred healthy age-matched nonsmoker students were studied. They were categorized into two groups on the basis of their residence: commuters and living on campus. Peak expiratory flow (PEF) recordings were made twice daily for 2 days with the Pink City Flow Meter. The measurement was then used to calculate for each subject the amplitude percentage mean, which is an index for expressing PEF variability for epidemiological purposes (Higgins BG, Britton JR, Chinns Jones TD, Jenkinson D, Burnery PG, Tattersfield AE. Distribution of peak expiratory flow variability in a population sample. Am Rev Respir Dis 1989; 140:1368-1372). Air pollution parameters were quantified by measurement of sulfur dioxide (SO2), oxides of nitrogen (NO2), carbon monoxide (CO), and respirable suspended particulate matter (RSPM) in the ambient air at the campus and on the roadside. The mean values of PEF variability (amplitude percent mean) in the students living on campus and in the commuters were 5.7 +/- 3.2 and 11 +/- 3.6, respectively (P < .05). Among the commuters, maximum number of subjects showed amplitude percentage mean PEFR at the higher end of variability distribution, as compared to the students living on campus, among whom the majority of subjects fell in the lower ranges of variability distribution. The ambient air quality parameters, namely SO2, NO2, CO, and RSPM were significantly lower on the campus. It can be concluded that long-term periodic exposure to air pollution can lead to increased PEF variability even in healthy subjects. Measurement of PEF variability may prove to be a simple test to measure effect of air pollution in healthy subjects.  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