全文获取类型
收费全文 | 8985篇 |
免费 | 404篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 101篇 |
儿科学 | 192篇 |
妇产科学 | 180篇 |
基础医学 | 1122篇 |
口腔科学 | 306篇 |
临床医学 | 728篇 |
内科学 | 2208篇 |
皮肤病学 | 124篇 |
神经病学 | 811篇 |
特种医学 | 300篇 |
外科学 | 1259篇 |
综合类 | 53篇 |
一般理论 | 7篇 |
预防医学 | 608篇 |
眼科学 | 113篇 |
药学 | 646篇 |
中国医学 | 6篇 |
肿瘤学 | 660篇 |
出版年
2023年 | 36篇 |
2022年 | 87篇 |
2021年 | 168篇 |
2020年 | 100篇 |
2019年 | 165篇 |
2018年 | 207篇 |
2017年 | 189篇 |
2016年 | 177篇 |
2015年 | 194篇 |
2014年 | 320篇 |
2013年 | 437篇 |
2012年 | 619篇 |
2011年 | 624篇 |
2010年 | 379篇 |
2009年 | 345篇 |
2008年 | 528篇 |
2007年 | 520篇 |
2006年 | 567篇 |
2005年 | 500篇 |
2004年 | 468篇 |
2003年 | 473篇 |
2002年 | 441篇 |
2001年 | 67篇 |
2000年 | 61篇 |
1999年 | 73篇 |
1998年 | 96篇 |
1997年 | 94篇 |
1996年 | 81篇 |
1995年 | 83篇 |
1994年 | 68篇 |
1993年 | 66篇 |
1992年 | 62篇 |
1991年 | 70篇 |
1990年 | 71篇 |
1989年 | 65篇 |
1988年 | 68篇 |
1987年 | 45篇 |
1986年 | 41篇 |
1985年 | 55篇 |
1984年 | 50篇 |
1983年 | 42篇 |
1982年 | 60篇 |
1981年 | 38篇 |
1980年 | 41篇 |
1979年 | 35篇 |
1978年 | 43篇 |
1977年 | 37篇 |
1975年 | 35篇 |
1974年 | 23篇 |
1973年 | 26篇 |
排序方式: 共有9424条查询结果,搜索用时 15 毫秒
51.
A new technique to investigate the motor unit organisation in man is described. By moving an EMG electrode through the motor unit a continuous scan or "electrophysiological cross section" is obtained. Computer processing methods are used for analysis and display. Examples are shown from healthy subjects and from patients with neuromuscular diseases. 相似文献
52.
Gunnar Skarping Torhjörn Brorson Carsten Sangö 《International archives of occupational and environmental health》1991,63(2):83-88
Summary Five men were exposed to toluene diisocyanate (TDI) atmospheres for 7.5 h. The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The mean air concentration of TDI was ca. 40 g/m3, which corresponds to the threshold limit value (TLV) of Sweden. The inhaled doses of 2,4- and 2,6-TDI were ca. 120 g. TDI in the test chamber air was determined by an HPLC method using the 9-(N-methyl-aminomethyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. After hydrolysis of plasma and urine, the related amines, 2,4- and 2,6-toluenediamine 2,4-, and 2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas-chromatography using selected ion monitoring (SIM) in the electron-impact mode. The urinary elimination of the TDAs showed a possible biphasic pattern, with rapid first phases for 2,4-TDA (mean t
1/2 for the concentration in urine, 1.9 h) and for 2,6-TDA (mean t
1/2 for the concentration in urine, 1.6 h). The cumulative amount of 2,4-TDA excreted in urine within 28 h ranged from 8% to 14% of the estimated dose of 2,4-TDI, and the cumulative amount of 2,6-TDA in urine ranged from 14% to 18% of the 2,6-TDI dose. The average urinary level of 2,4-TDA was 5 g/l in the 6 to 8-h sample (range 2.8–9.6 g/l), and the corresponding value for 2,6-TDA was 8.6 g/l (range, 5.6–16.6 g/l). Biological monitoring of exposure to 2,4- and 2,6-TDI by analysis of 2,4- and 2,6-TDA in urine is feasible. 相似文献
53.
L Matheson V Mooney V Caiozzo G Jarvis J Pottinger C DeBerry K Backlund K Klein J Antoni 《Spine》1992,17(8):914-921
Although isokinetic strength testing has been in use for more than two decades, and numerous studies have addressed isokinetic performance of the lumbar spine, the effect of instructions on isokinetic trunk strength has not been studied. In a sample of 30 healthy women, this study examined the effect of "high-demand" instructions on lumbar strength performance. High-demand instructions were found to have a substantial positive effect on performance variability, reliability, absolute magnitude, and validity. Under these conditions, isokinetic trunk strength was found to be predictive of performance in a frequent lifting-lowering task. 相似文献
54.
Carl-Gustaf Elinder Jan Andersson Gunilla Bolinder Gunnar Tydén 《Transplant international》1992,5(2):81-84
We retrospectively examined the effectiveness of prophylaxis with cotrimoxazole in preventing Pneumocystis carnii pneumonia in recipients of kidney and combined kidney-pancreas transplants between 1985 and 1989. Cotrimoxazole prophylaxis (480 mg daily or 300 mg/m2), when used, was started within 2 months after transplantation and usually continued until 6 months after surgery. Eight (3.7%) of the 214 patients who were not given prophylaxis were infected with Pneumocystis carinii, and there were 4 fatalities (50% mortality). There were no cases among the 161 patients given prophylaxis (P 0.03). No serious adverse effects were noted in the prophylaxis group. It is concluded that prophylaxis against Pneumocystis carinii infection is well tolerated and should be given as soon as possible to all organ transplant recipients for at least 6 months. 相似文献
55.
Efficiency of adjuvant immunochemotherapy following curative resection in patients with locally advanced gastric cancer 总被引:3,自引:0,他引:3
Tadeusz Popiela Jan Kulig Antoni Czupryna Antoni M. Szczepanik Marek Zembala 《Gastric cancer》2004,7(4):240-245
Background Despite curative resection, 50%–90% of gastric cancer patients die of disease relapse. Although some clinical trials have indicated that chemotherapy and immunochemotherapy may be effective modalities, more recent studies have not been able to define the standard treatment for advanced gastric cancer. The present study evaluated the effect of adjuvant immunochemotherapy with the use of BCG (bacille Calmette-Guérin) and FAM (5-fluorouracil, adriamycin, mitomycin C) chemotherapy on the survival of patients with locally advanced resectable gastric cancer.Methods A total of 156 patients with stage III or IV gastric cancer who had undergone curative resection were randomly assigned to three treatment groups: BCG + FAM (immunochemotherapy), FAM (chemotherapy), and control (surgery only). Treatment was continued for 2 years or until death. Further postsurgical follow up was carried on for up to 10 years.Results Overall 10-year survival was 47.1% for the immunochemotherapy group (P < 0.037 vs FAM and P < 0.0006 vs control), 30% for the chemotherapy group (vs control, NS), and 15.2% for the control group. In patients with pT2/T3 primary tumors, 10-year survival was 55.3% for BCG + FAM vs 28.2% for FAM (P < 0.01) and 14.6% for the control group (P < 0.00018). BCG + FAM signifi-cantly improved the survival of patients with intestinal-type but not diffuse-type cancer. Immunochemotherapy was well tolerated.Conclusion This study, based on a limited number of patients, indicates that adjuvant immunochemotherapy (BCG + FAM) may prolong the survival of gastric cancer patients after curative gastrectomy; in particular, in patients with pT2/T3 tumors and intestinal-type primary tumors. There was no survival benefit from FAM adjuvant chemotherapy. 相似文献
56.
57.
Methanol is a widely used solvent and a potential fuel for motor vehicles. Human kinetic data of methanol are sparse. As a basis for biological exposure monitoring and risk assessment, we studied the inhalation toxicokinetics of methanol vapor in four female and four male human volunteers during light physical exercise (50 W) in an exposure chamber. The relative uptake of methanol was about 50% (range 47-53%). Methanol in blood increased from a background level of about 20 to 116 and 244 microM after 2 h exposure at 0, 100 ppm (131 mg/m3) and 200 ppm (262 mg/m3), respectively. Saliva showed substantially higher levels than blood immediately after exposure. This difference disappeared in a few minutes; thereafter the concentrations and time courses in blood, urine, and saliva were similar, with half times of 1.4, 1.7, and 1.3 h, respectively. The postexposure decrease of methanol in exhaled air was faster, with a half time of 0.8 h. The methanol concentrations were approximately twice as high in all four types of biological samples at 200 compared to 100 ppm. No increase in urinary formic acid was seen in exposed subjects. Our study indicates non-saturated, dose-proportional kinetics of methanol up to 200 ppm for 2 h. No gender differences were detected. Similar, parallel patterns were seen with regard to the methanol time courses in blood, urine, and saliva, whereas the concentration in exhaled air decreased markedly faster. Thus, apart from blood and urine, saliva also seems suitable for biomonitoring of methanol exposure. 相似文献
58.
Raghavendra Vasudeva Murthy Gunnar Arbman Jingfang Gao G David Roodman Xiao-Feng Sun 《Clinical cancer research》2005,11(6):2293-2299
PURPOSE: Legumain, a novel asparaginyl endopeptidase, has been observed to be highly expressed in several types of tumors including colorectal cancer. However, there is no study examining the relationship of legumain expression to clinocopathologic and biological variables in colorectal cancers. EXPERIMENTAL DESIGN: We investigated legumain expression in 164 primary colorectal cancers, 34 corresponding distant normal mucosa samples, 89 adjacent normal mucosa samples, and 33 lymph node metastases using immunohistochemistry. We also did Western blotting analysis on three additional colorectal cancers and three colonic cell lines. RESULTS: Legumain expression was increased in primary tumors compared with distant or adjacent normal mucosa (P < 0.05), but there was no significant change between primary tumors and metastases (P > 0.05). Legumain expression was positively related to poorer differentiation/mucinous carcinoma (P = 0.04), higher degree of necrosis (P = 0.03) and apoptosis (P < 0.0001), positive proliferating cell nuclear antigen (P < 0.0001) and p53 expression (P = 0.049), and had a positive tendency towards stromelysin 3 (P = 0.058) and PINCH positivity (P = 0.05). The patients with tumors that showed both weak and lower percentage of the legumain expression, either in tumor (P = 0.01) or in stroma (P = 0.04), had a better prognosis. CONCLUSIONS: The legumain expression may be involved in colorectal cancer development and have a prognostic value in the patients. 相似文献
59.
Pedro Kringen Yun Wang Vanessa Dumeaux Jahn M Nesland Gunnar Kristensen Anne-Lise Borresen-Dale Anne Dorum 《BMC cancer》2005,5(1):134
Background
Ovarian carcinomas from 30 BRCA1 germ-line carriers of two distinct high penetrant founder mutations, 20 carrying the 1675delA and 10 the 1135insA, and 100 sporadic cases were characterized for somatic mutations in the TP53 gene. We analyzed differences in relation to BRCA1 germline status, TP53 status, survival and age at diagnosis, as previous studies have not been conclusive. 相似文献60.
Gro Tunheim Gunnar
yvind Isaksson R Adity Chopra Audun Aase AnneMarte Bakken Kran John Torgils Vaage Fridtjof LundJohansen Olav Hungnes 《Influenza and other respiratory viruses》2022,16(6):1004
BackgroundOne year into the COVID‐19 pandemic, the cumulative number of confirmed COVID‐19 cases in Norway was still low. In January 2021, when the Norwegian COVID‐19 vaccination campaign started, the national seroprevalence estimate of SARS‐CoV‐2 antibodies was 3.2%. We have conducted a nationwide cross‐sectional study in August 2021 to investigate the overall prevalence of SARS‐CoV‐2 antibodies in Norway after 8 months of COVID‐19 mass vaccination and a third wave of SARS‐CoV‐2 infection.MethodsResidual sera were collected from laboratories across Norway in August 2021. In IgG antibodies against the spike protein, the spike receptor binding domain (RBD) and the nucleocapsid protein of SARS‐CoV‐2 were measured by a bead‐based flow cytometric assay.ResultsIn total, 1926 residual sera were collected from individuals aged 0–98 years; 55.1% were from women. The overall national estimated seroprevalence from vaccination and/or infection was 62.6% (credible interval [CrI] 60.1%–65.2%) based on having antibodies against both spike and RBD. Estimated seroprevalence increased with age. Among all samples, 11.7% had antibodies against nucleocapsid. For unvaccinated children <12 years, the seroprevalence estimate due to SARS‐CoV‐2 infection was 12.5% (95% CrI 9.3%–16.1%). Of seropositive samples from the unvaccinated children, 31.9% lacked anti‐nucleocapsid antibodies.ConclusionsThe high overall SARS‐CoV‐2 seroprevalence estimates are in line with Norwegian registry data. Vaccination, not infection, contributed the most to the high seroprevalence in August 2021. Lack of antibodies against nucleocapsid should not automatically be interpreted as absence of previous infection as this could lead to underestimation of COVID‐19 cases in seroprevalence studies. 相似文献