全文获取类型
收费全文 | 2399篇 |
免费 | 139篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 104篇 |
儿科学 | 84篇 |
妇产科学 | 172篇 |
基础医学 | 294篇 |
口腔科学 | 77篇 |
临床医学 | 254篇 |
内科学 | 411篇 |
皮肤病学 | 13篇 |
神经病学 | 240篇 |
特种医学 | 175篇 |
外科学 | 272篇 |
综合类 | 11篇 |
一般理论 | 1篇 |
预防医学 | 172篇 |
眼科学 | 17篇 |
药学 | 177篇 |
肿瘤学 | 72篇 |
出版年
2022年 | 16篇 |
2021年 | 36篇 |
2020年 | 17篇 |
2019年 | 36篇 |
2018年 | 44篇 |
2017年 | 36篇 |
2016年 | 49篇 |
2015年 | 48篇 |
2014年 | 43篇 |
2013年 | 80篇 |
2012年 | 96篇 |
2011年 | 76篇 |
2010年 | 46篇 |
2009年 | 56篇 |
2008年 | 77篇 |
2007年 | 130篇 |
2006年 | 104篇 |
2005年 | 98篇 |
2004年 | 90篇 |
2003年 | 84篇 |
2002年 | 91篇 |
2001年 | 94篇 |
2000年 | 86篇 |
1999年 | 67篇 |
1998年 | 52篇 |
1997年 | 38篇 |
1996年 | 41篇 |
1995年 | 23篇 |
1994年 | 17篇 |
1993年 | 26篇 |
1992年 | 40篇 |
1991年 | 27篇 |
1990年 | 39篇 |
1989年 | 34篇 |
1988年 | 32篇 |
1987年 | 39篇 |
1986年 | 37篇 |
1985年 | 45篇 |
1984年 | 32篇 |
1983年 | 18篇 |
1982年 | 19篇 |
1981年 | 17篇 |
1980年 | 20篇 |
1979年 | 21篇 |
1978年 | 23篇 |
1977年 | 29篇 |
1976年 | 20篇 |
1975年 | 36篇 |
1973年 | 27篇 |
1940年 | 15篇 |
排序方式: 共有2546条查询结果,搜索用时 0 毫秒
91.
Exposure to motor vehicle traffic and allergic sensitization. The Swiss Study on Air Pollution and Lung Diseases in Adults (SAPALDIA) Team 总被引:5,自引:0,他引:5
Wyler C Braun-Fahrländer C Künzli N Schindler C Ackermann-Liebrich U Perruchoud AP Leuenberger P Wüthrich B 《Epidemiology (Cambridge, Mass.)》2000,11(4):450-456
We examined the association between the presence of an allergic sensitization and seasonal allergic diseases or symptoms and the exposure to road traffic in Basel, Switzerland. Traffic counts at the domiciles of subjects ranged from 24 to 32,504 cars per 24 hours, with a median of 1,624. To investigate the relation of road traffic and allergies, we matched the data of the traffic inventory of Basel with those of the 820 participants of the SAPALDIA study (Swiss Study on Air Pollution and Lung Diseases in Adults), ages 18-60 years, who had completed a detailed respiratory health questionnaire and had undergone allergy testing (skin prick tests and serologic examinations). We observed a positive association with a sensitization to pollen that was most pronounced among persons with a duration of residence of at least 10 years. The odds ratios (adjusted for educational level, smoking behavior, number of siblings, age, sex, and family history of atopy) for cars, contrasting four exposure categories with the lowest quartile as referent category, were 1.99 [95% confidence interval (CI) = 0.91-4.38], 2.47 (95% CI = 1.06-5.73), and 2.83 (95% CI = 1.26-6.31). These results suggest that living on busy roads is associated with a higher risk for a sensitization to pollen and could possibly be interpreted as an indication for interactions between pollen and air pollutants. We did not, however, find a similar relation between motor vehicle traffic and hay fever or seasonal allergic symptoms, and we saw no trend that increasing traffic exposure was associated with a rise in sensitization rates to indoor allergens. 相似文献
92.
A recent report from our laboratory describes techniques for growing fetal murine endolymphatic sac (ELS) in vitro in tissue culture. The purpose of the present study is twofold: first, to determine whether the in vitro endolymphatic cells function in their artificial environment; and second, to begin to understand the nature of luminal cell function in vitro when separated from subepithelial connective tissue and blood. The endolymphatic sac was dissected from 18th gestational day fetal mouse otocysts and grown in DME tissue culture media for 7 days. Light microscopic sections of the endolymphatic sac were stained with Periodic Acid Schiff (PAS) reagent, alcian blue, Verhoff's elastin stain, and van Gieson's collagen stain to reveal deposits of glycogen as well as mucopolysaccharides, elastic fibers, and collagen. Controls for glycogen staining were prepared using the amylase enzyme. For electron microscopical evaluation, 'en bloc' staining was used, to confirm the location of cellular glycogen. Results indicate that in vitro luminal cells of the murine ELS are viable and show signs of functional activity with the markers used. The luminal substance and apical cytoplasm shows distinct purple metachromasia with toluidine blue and PAS-positive staining that disappears with amylase digestion. The ELS cells and luminal substance were negative for alcian blue at pH 1.0 and pH 2.5. These findings are similar to those seen in in vivo murine control sac specimens and demonstrate the ability of cultured sac cells to store glycogen and produce complex carbohydrates. The similarity in staining between the luminal substance and the cytoplasm of sac cells in all in vitro specimens suggests some secretory function by sac cells. 相似文献
93.
DC Wilson MJ Cunningham MMcC Reid SS Johnston TF Fannin 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(1):84-85
A baby with unilateral cleft lip, midline cleft palate and hypertelorism developed meningitis in the first 48 h of life. Examination of the nasopharynx showed a soft tissue mass, which was confirmed as a basal encephalocele by computed tomography. There was also congenital hydrocephalus and the corpus callosum was absent. Surgical treatment included repair of the anterior basal skull defect, repair of the lip and palate, and ventriculo-peritoneal shunt. There is currently evidence of developmental delay and right-sided visual impairment due to Morning Glory syndrome. This case demonstrates that basal encephalocele should be considered in any baby with midline facial deformity who develops meningitis. 相似文献
94.
The endolymphatic sac is believed to play a major role in membranous labyrinth homeostasis by controlling the volume of endolymph, removing debris, and participating in the immune response of the inner ear. The endolymphatic sac is postulated to absorb endolymph and to synthesize and secrete high-molecular-weight and osmotically active glycosaminoglycans (GAGs). The present study examines the ability of in vitro adult guinea pig endolymphatic sac cells to synthesize complex proteins and polysaccharides. The intent is to characterize the nature of these compounds by studying carbon-14 (14C) glucose incorporation in tissue cultured endolymphatic sac specimens using autoradiographic and specific enzymatic digestion techniques. Our results suggest that sac cells can synthesize GAGs and proteins in vitro in proportionately larger amounts than surrounding connective tissue and dura. The principal GAG synthesized by the endolymphatic sac appears to be hyaluronan. 相似文献
95.
PC Ng J Hiu TF Fok EAS Nelson KL Cheung W Wong 《Acta paediatrica (Oslo, Norway : 1992)》1995,84(8):955-956
We report an unusual case of localized congenital tuberculosis otitis in a preterm infant. Unlike disseminated congenital cases, the manifestations of localized otitis are associated with a triad of signs: (i) regional lymphadenopathy in the absence of typical systemic features of tuberculosis; (ii) delayed onset of presentation; and (iii) refractory otitis unresponsive to conventional antimicrobial agents. The need for greater diligence in looking for neonatal tuberculosis is emphasized, especially in an ethnic or socioeconomic environment where the disease is prevalent. Congenital tuberculosis, otitis, preterm
PC Ng, Department of Paediatrics, Level 6, Clinical Sciences Building, Prince of Wales Hospital, Shatin, NT, Hong Kong 相似文献
PC Ng, Department of Paediatrics, Level 6, Clinical Sciences Building, Prince of Wales Hospital, Shatin, NT, Hong Kong 相似文献
96.
P Bischof A M Schindler R Wyss W L Herrmann P C Sizonenko 《Archives of gynecology》1986,237(3):109-116
Pregnancy-associated plasma protein-A (PAPP-A) is a macromolecular glycoprotein produced in increasing concentration as pregnancy advances. PAPP-A is not specific to pregnancy since measurable levels have been found in non-pregnant females and in males. In non-pregnant females, PAPP-A is probably produced by the endometrium. The origin of PAPP-A in pregnant women is still controversial. In-vitro trophoblast and decidual explants both produce PAPP-A. So far, it is not known if the same applies to the in-vivo situation and to what extent these two tissues contribute to the circulating levels of PAPP-A. This study compares the circulating concentrations of PAPP-A and beta-hCG and progesterone in different pathological situations. In hydatidiform moles, beta-hCG levels are very high demonstrating an intense trophoblastic activity, whereas PAPP-A levels remain in the normal range. With spontaneous abortions, beta-hCG levels decline to very low values whereas PAPP-A continues to increase. These observations furnish indirect evidence for a major contribution to circulating PAPP-A levels by extratrophoblastic sites. Furthermore, PAPP-A levels decrease after administration of an anti-progesterone (RU486) either in-vivo or in-vitro. This is considered as a proof that PAPP-A levels in early pregnancy are progesterone dependent. 相似文献
97.
R A Schindler D K Kessler S J Rebscher J Yanda 《Otolaryngologic clinics of North America》1986,19(2):287-305
Using a four-channel implant system with a vocoder-based processor developed at UCSF over an extensive period of research, clinical trials of the UCSF/Storz device were initiated in February 1985 under the sponsorship of Storz Instrument Company. To date, 13 patients have been implanted with the UCSF/Storz device, 10 of whom have been fitted with their external processor and transmitter and have received at least their initial postoperative evaluations. Of these 10 patients, nine are able to use all four channels of their implant system. The device fitting/adjusting process for these patients has been remarkably easy, requiring only approximately 30 to 60 minutes. Patient results have been extremely good, with eight of the 10 patients obtaining some open-set auditory only speech understanding. Without extensive rehabilitation and training, most patients have demonstrated an improvement in speech reception over time. Lip-reading and tracking results indicate that all patients have attained an enhancement of lip-reading ability with the use of the device, suggesting that improved general communication skills have been provided for each UCSF/Storz patient. 相似文献
98.
Using the four channel cochlear implant system with a vocoder-based processor developed at UCSF over an extensive period of research, clinical trials of the UCSF/Storz device were initiated in February 1985, under the sponsorship of Storz Instrument Company. To date, 13 patients have been implanted with this device, nine of whom have been fitted with their external processor and transmitter and have received at least their initial postoperative evaluation. Patient results have been extremely promising, with eight of the nine patients obtaining some open-set auditory only speech understanding. Most patients have demonstrated improvement over time and all patients have attained an enhancement in lipreading ability with the use of the UCSF/Storz device. 相似文献
99.
Sixteen patients have been implanted with the UCSF/Storz multichannel implant, 11 of whom have been fitted with their external speech processors and transmitters and administered postoperative audiological evaluations. Both the surgical procedures used and the hearing results for these patients are presented. The potential medical/surgical complications of implant surgery and the future direction of research and development within the UCSF/Storz implant program are discussed. 相似文献
100.
The influence of the progestogens hydroxyprogesteroncaproate , norethisteronacetate and d-norgestrel on the growth of endometrial cancer was observed on 78 cell cultures. 40 cases revealed an influence on in vitro growth by at least one progestogen, 26 times by progesterone, 21 times by norethisterone and 20 times by norgestrel. In 17 cases two or more progestogens had an effect on in vitro growth, however, in 23 cases only one progestogen revealed an effect. The possible consequences of these results for the planning of therapy are discussed. 相似文献