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   7987篇
  免费   531篇
  国内免费   50篇
耳鼻咽喉   120篇
儿科学   171篇
妇产科学   127篇
基础医学   971篇
口腔科学   270篇
临床医学   679篇
内科学   1685篇
皮肤病学   165篇
神经病学   516篇
特种医学   315篇
外国民族医学   2篇
外科学   1250篇
综合类   136篇
一般理论   5篇
预防医学   548篇
眼科学   362篇
药学   731篇
中国医学   73篇
肿瘤学   442篇
  2024年   9篇
  2023年   99篇
  2022年   202篇
  2021年   378篇
  2020年   249篇
  2019年   315篇
  2018年   403篇
  2017年   270篇
  2016年   329篇
  2015年   319篇
  2014年   469篇
  2013年   571篇
  2012年   800篇
  2011年   793篇
  2010年   461篇
  2009年   324篇
  2008年   513篇
  2007年   474篇
  2006年   363篇
  2005年   297篇
  2004年   224篇
  2003年   232篇
  2002年   176篇
  2001年   34篇
  2000年   24篇
  1999年   34篇
  1998年   24篇
  1997年   13篇
  1996年   17篇
  1995年   13篇
  1994年   12篇
  1993年   12篇
  1992年   4篇
  1991年   9篇
  1990年   4篇
  1989年   11篇
  1988年   11篇
  1987年   4篇
  1986年   2篇
  1985年   5篇
  1984年   5篇
  1982年   8篇
  1981年   4篇
  1980年   4篇
  1979年   5篇
  1978年   7篇
  1977年   5篇
  1976年   8篇
  1975年   9篇
  1974年   6篇
排序方式: 共有8568条查询结果,搜索用时 46 毫秒
941.
942.
943.
A 75-year-old lady came to emergency room due to dizziness andpresyncopal attacks during exertion since two days prior toadmission. Transesophageal echocardiography revealed a thrombuslike mass in right atrium traversing patent foramen ovale andextending to left atrium. Spiral chest CT scan showed bilateralpulmonary thromboemboli. Operative and pathological findingsconfirmed the diagnosis.  相似文献   
944.
Objectives:   The role of endogenous cannabinoids in ischemia/reperfusion induced germ cell apoptosis in rats was investigated.
Methods:   Baseline group was for basal normal values. The Sham operated group served as a control group. The torsion/detorsion (T/D) group underwent torsion (1 h) and detorsion; AN1, AN2, and AN3 groups received anandamide (10 mg/kg) 30 min before torsion, 30 min after torsion, and just after detorsion, respectively. In the AM251 group, AM251 (0.5 mg/kg) was injected 45 min before torsion and in the AN/AM group, AM251 and anandamide were injected 45 and 30 min before torsion, respectively. Lipid peroxidation, antioxidant enzymes, and germ cell apoptosis was determined.
Results:   Malondialdehyde (MDA) levels in the T/D group were significantly higher than the control group. Moreover, MDA values in the AN1, AN2, and AN3 groups were significantly lower than T/D. There were significant decreases in catalase and superoxide dismutase activities in the T/D group versus the control group. These values in the AN1, AN2, and AN3 groups were significantly higher than T/D. It was also shown that MDA levels in the AN/AM group were significantly higher than the AN1 group. In the AN/AM group, catalase and superoxide dismutase activities were significantly lower versus the AN1 group. The mean germ cell apoptosis scores in all animals with testicular T/D were significantly higher than the control group. There was no difference between the apoptotic indices in the AN1, AN2, AN3, and T/D groups. Apoptosis scores in AM251 and AN/AM were significantly higher compared with the T/D and AN1 groups.
Conclusions:   Although anandamide increased antioxidant markers, it failed to reduce germ cell apoptosis. AM251 worsened the antioxidant defense system, which is reflected as higher germ cell apoptosis.  相似文献   
945.
Symptoms of lateral epicondylitis (LE) are attributed to degenerative changes and inflammatory reactions in the common extensor tendon induced by microscopic tears in the tissue after repetitive or overload functions of the wrist and hand extensor muscles. Conventional treatments, provided on the premise of inflammatory basis of LE, have shown 39-80% failure rate. An alternative approach suggests that symptoms of LE could be due to active tender points developed in the origin of hand and wrist extensor muscles after overuse or repetitive movements. Oscillating-energy Manual Therapy (OEMT), also known as V-spread, is a craniosacral manual technique that has been clinically used for treating tender points over the suture lines in the skull. Considering symptoms of LE may result from active tender points, the purpose of this study was to investigate the effect of OEMT on pain, grip strength, and functional abilities of subjects with chronic LE. Twenty-three subjects with chronic LE (>3mo) between ages of 24 and 72 years participated in this study. Before their participation, all subjects were screened to rule out cervical and other pathologies that could possibly contribute to their lateral elbow pain. Subjects who met the inclusion criteria were randomized into treatment and placebo treatment groups by a second (treating) therapist. Subjects were blinded to their group assignment. Subjects in the treatment group received OEMT for six sessions. During each treatment session, first a tender point was located through palpation. After proper hand placement, the therapist focused the direction of the oscillating energy on the localized tender point. Subjects in the placebo group underwent the same procedure, but the direction of the oscillating energy was directed to an area above or below the tender points, not covering the affected area. Jamar Dynamometer, Patient Specific Functional Scale (PSFS), and Numeric Rating Scale (NRS) were used to measure grip strength, functional status, and pain intensity and limited activity due to pain, respectively. The screening therapist who was blinded to the subjects' group assignment performed pretest, posttest, and six-month follow-up measurements. Subjects in the treatment group showed both clinically and statistically significant improvement in grip strength (p=0.03), pain intensity (p=0.006), function (p=0.003), and limited activity due to pain (p=0.025) compared with those in the placebo group. Follow-up data, collected after six months, showed no significant difference between posttest and follow-up measurements in functional activity (p=0.35), pain intensity (p=0.72), and activity limitation due to pain (p=0.34). Of all the subjects contacted for follow-up assessment, 91% maintained improved function and 73% remained pain free for at least six months. OEMT seems to be a viable, effective, and efficient alternative treatment for LE.  相似文献   
946.
947.
948.
The role of sex hormones in atherogenesis has not been well defined. Since hemodialysis patients show signs of feminization and an increased propensity for atherosclerosis they are particularly suited to probe the relationship between estrogen, testosterone, and atherosclerosis. Therefore, we measured plasma total, free, and protein-bound estradiol (E2), testosterone (Te), and prolactin in 28 hemodialysis patients and in 30 age-matched controls. Von Willebrand factor (vWF) levels were also assayed. Total and free E2 as well as Te were significantly decreased in the patients (p less than 0.001). However, the E2/Te ratio was elevated in the patients (p = 0.05), as was vWF (p less than 0.01). No correlations were found between hormone levels and vWF, gynecomastia or vascular disease, but vWF and vascular disease were highly correlated. We conclude that in hemodialysis patients absolute estrogen levels are lower than normal, but that the estrogen/androgen ratio is shifted in favor of estrogen because of the coexistence of androgen deficiency. These findings suggest that an elevation in the estrogen/androgen ratio, rather than an increase in estrogen per se, may be a risk factor for atherosclerosis.  相似文献   
949.
A new synthetic approach for the preparation of polymer supports/polymeric reagents is reported. The method is based on the chemistry of activated esters, and it is generally simpler than the methods conventionally employed for the preparation of funcationalized resins. Thus, the details of a series of beaded, and predominantly alternate, poly(styrene-co-2,4,5-trichlorophenyl acrylate)s is given. These activated resins were readily converted into highly functionalized poly(styrene-co-acrylamide) resins by aminolysis with a functional groups carrying amine. Resins with low degrees of functionality were obtained by partial aminolysis of the activated resins with a simples amine, and subsequent reaction with a functional group carrying nucleophile, or vice versa. A number of the new resins were examined for their swelling behaviour in a wide range of solvents and were found to show a considerably more general solvent compatibility than either styrene- or N,N-dimethylacrylamide-based resins. The relatively general solvent compatibility of the new resins is briefly discussed in terms of their copolymer structure and its is suggested that the dual “hydrophobic-hydrophilic”, character of these resins may be of important practical implications in, among others, solid phase peptide synthesis.  相似文献   
950.
Summary: Vulvovaginal mycosis is primarily caused by 2 species of fungi, Candida albicans and Torulopsis glabrata. Certain clinical characteristics of vulvovaginal mycosis caused by different fungi were studied. Of the 314 cases of vulvovaginal mycosis, 259 were caused by C. albicans, 24 by Candida species other than C. albicans, 27 by T. glabrata, one by Rhodotorula, and 3 by C. albicans and T. glabrata together. The age distribution showed significantly more patients (p <0.01) under the age of 30 in the C. albicans group in the T. glabrata group. Significantly fewer (p <0.05) non-pregnant women belonged to the C. albicans than to the non-albicans Candida group; the number also seemed smaller than in the T. glabrata group (p <0.10). The number of cases with leukorrhea only was significantly lower (p <0.01) in the C. albicans than in the T. glabrata group. Whether patients were single or married, nulliparous or multiparous, users of antibiotics or hormones revealed no differences. Zusammenfassung: Die Vulvovaginalmykose wird hauptsächlich von zwei Pilzarten verursacht: Candida albicans und Torulopsis glabrata. Im vorliegenden Beitrag wird die ätiologie dieser Erkrankung in einem Patientinnenkollektiv statistisch untersucht. Es zeigte sich, daß von 314 Fällen vulvovaginal Mykose 259 auf C. albicans, 24 auf andere Candida-Species als C. albicans, 27 auf T. glabrata, einer auf Rhodotorula und 3 auf Mischinfektionen durch C. albicans und T. glabrata zurückzuführen waren. Hinsichtlich der Altersverteilung kamen jüngere als 30 Jahre alte Patientinnen statistisch signifikant häufiger (p <0.01) in der C. albicans-Gruppe als in der T. glabrata-Gruppe vor. Eine signifikant geringere Anzahl nicht-schwangerer Frauen (p <0.05) ist in der C. albicans-Gruppe, verglichen mit der nicht-albicans Candida-Gruppe wie auch mit der T. glabrata-Gruppe (p <0.10), enthalten. Fälle mit Leukorrhoe allein fand sich statistisch signifikant seltener in der C. albicans- als in der T. glabrata-Gruppe (p <0.01). Ob die Patientinnen ledig oder verheiratet, Nullipara oder Multipara waren oder ob sie Antibiotika oder Hormone nahmen zeigte keine statistisch signifikanten Unterschiede.  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