全文获取类型
收费全文 | 18281篇 |
免费 | 1351篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 152篇 |
儿科学 | 392篇 |
妇产科学 | 406篇 |
基础医学 | 2824篇 |
口腔科学 | 280篇 |
临床医学 | 1874篇 |
内科学 | 4038篇 |
皮肤病学 | 324篇 |
神经病学 | 1735篇 |
特种医学 | 607篇 |
外国民族医学 | 4篇 |
外科学 | 2761篇 |
综合类 | 186篇 |
一般理论 | 5篇 |
预防医学 | 1368篇 |
眼科学 | 321篇 |
药学 | 1104篇 |
中国医学 | 9篇 |
肿瘤学 | 1284篇 |
出版年
2022年 | 127篇 |
2021年 | 340篇 |
2020年 | 167篇 |
2019年 | 322篇 |
2018年 | 398篇 |
2017年 | 252篇 |
2016年 | 251篇 |
2015年 | 341篇 |
2014年 | 464篇 |
2013年 | 636篇 |
2012年 | 935篇 |
2011年 | 978篇 |
2010年 | 490篇 |
2009年 | 510篇 |
2008年 | 858篇 |
2007年 | 844篇 |
2006年 | 853篇 |
2005年 | 743篇 |
2004年 | 741篇 |
2003年 | 684篇 |
2002年 | 665篇 |
2001年 | 561篇 |
2000年 | 602篇 |
1999年 | 469篇 |
1998年 | 176篇 |
1997年 | 156篇 |
1996年 | 144篇 |
1995年 | 121篇 |
1994年 | 134篇 |
1993年 | 109篇 |
1992年 | 372篇 |
1991年 | 344篇 |
1990年 | 365篇 |
1989年 | 323篇 |
1988年 | 333篇 |
1987年 | 310篇 |
1986年 | 321篇 |
1985年 | 283篇 |
1984年 | 214篇 |
1983年 | 174篇 |
1979年 | 166篇 |
1978年 | 165篇 |
1977年 | 138篇 |
1976年 | 110篇 |
1975年 | 156篇 |
1974年 | 185篇 |
1973年 | 138篇 |
1972年 | 138篇 |
1971年 | 139篇 |
1970年 | 123篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Radiotherapy has been successful in treating localized prostate cancer; however, a subset of patients will experience disease
recurrence. Determination of the recurrence location must be made using pretreatment and posttreatment clinical variables,
imaging, and postradiotherapy biopsy. Patients presumed to have local-only recurrence, optimal clinical risk factors, and
an extended life expectancy may be considered for salvage local treatment. Current options include salvage surgery, cryoablation,
and brachytherapy. Although they are associated with higher morbidity than primary therapy, salvage treatments can be effective
and can still provide patients with a good oncologic and functional outcome. As these modalities continue to improve and patient
selection is optimized, better results will evolve. 相似文献
22.
Fabia Preminger Patrice L Weiss Naomi Weintraub 《The American journal of occupational therapy》2004,58(2):193-201
PURPOSE: To determine whether there is a correlation between handwriting and keyboarding speed and accuracy, and whether handwriting and keyboarding share common underlying components. METHODS: Sixty-three typically developing 5th-grade students attended a series of 15 keyboarding lessons for a total of 5 hours. Prior to the lessons, cognitive, sensory, and motor skills related to handwriting were evaluated. Prior to and following the lessons keyboarding and handwriting accuracy and speed were also tested. Correlations were employed to examine relationships between handwriting and keyboarding skills and multiple regression analyses were used to examine the contribution of performance components to handwriting and keyboarding performance. RESULTS: Following keyboarding instruction, a significant correlation was found between handwriting and keyboarding speed, but not in accuracy of these tasks. Similarly, some of the specific tests measuring tactile and oculo-motor functions were found to be related to both handwriting and keyboarding speed, yet accuracy of these tasks did not share common underlying components. CONCLUSIONS: It appears that handwriting and keyboarding accuracy may entail different skills, suggesting that keyboarding may be a potential alternative writing tool for students with handwriting difficulties. It also appears that when students write slowly, handwriting speed should be considered prior to recommending keyboarding for these students. Additional research is required to further support these findings. 相似文献
23.
24.
Alexander Dullenkopf Goran Lamesic Andreas Gerber Markus Weiss 《Journal canadien d'anesthésie》2003,50(5):507-510
PURPOSE: A simple technical solution is presented to provide video transmission from the tip of a Bullard laryngoscope to a bedside video display, while the operator is still able to look through the viewing ocular of the Bullard laryngoscope during tracheal intubation. EQUIPMENT: This is achieved by insertion of an ultrathin fibreoptic video-endoscopic system into the working channel of the Bullard laryngoscope. Thereby the view from the distal blade tip is transmitted to a bedside monitor, without interfering with the use of the Bullards laryngoscope's original eyepiece. The presented technical solution allows video transmission without considerable additional weight normally associated with attaching video endoscopy cameras, light and camera cables to endoscopic devices. Thus, the Bullard laryngoscope remains lightweight and easy to maneuver. A screw-threaded adapter with a side-port is proposed to prevent displacement of the fibreoptic cable while still allowing application of oxygen. CONCLUSION: Experience and skills with tracheal intubation using the presented video-enhanced Bullard laryngoscope can be achieved in the originally intended way, while the supervisor or attending viewers can follow the tracheal intubation procedure on the video display. 相似文献
25.
Ohne Zusammenfassung 相似文献
26.
27.
Accumulation of somatic mutants in the B cell compartment after primary immunization with a T cell-dependent antigen. 总被引:4,自引:0,他引:4
The accumulation of somatic mutants in splenic B lymphocytes early after primary immunization with the hapten (4-hydroxy-3-nitro-phenyl)acetyl (NP) coupled to chicken gamma globulin (CG) was determined. Rearranged V186.2 heavy chain genes were amplified by the polymerase chain reaction from genomic DNA and subjected to nucleotide sequence analysis. Somatic antibody mutants become detectable on day 6 after immunization, and most of the somatic mutations accumulating in the memory compartment are introduced until day 14. At this time strong selection for mutants expressing high binding affinity for NP is apparent. Extrapolation from the mutation frequency increases between day 6 and day 14 to the previously determined mutation frequency at week 6 (Weiss. U. and Rajewsky, K., J. Exp. Med. 1990, 172: 1681) leads to the prediction that the process of mutant generation ceases to operate around day 22 after primary immunization. 相似文献
28.
29.
Purpose. Flexible parametric models describing the input process after extravascular drug administration are needed for the assessment of absorption rate and the use of population methods in bioavailability and bioequivalence studies.
Methods. The oral concentration-time curve modeled as the product of the input and disposition function in the Laplace domain was obtained by numerical inversion methods for parameter estimation. The utility of the inverse Gaussian input density was examined using bioavailability data of an extended-release dosage form. Measures of rate of absorption and the cumulative absorbed amount profile were defined in terms of the estimated model parameters.
Results. Accurate estimation of absorption parameters was achieved by simultaneous fitting of the extravascular and intravascular data (describing the latter by a triexponential function). The new input function allowed a direct estimation of both extent of absorption and mean absorption time.
Conclusions. The findings suggest that the inverse Gaussian density is a useful input function. Its flexibility may reduce the effect of model misspecification in parameter estimation. All parameters can be readily interpreted in terms of the absorption process. 相似文献
30.
Differences in O2 delivery and consumption along the fed and fasted small intestine are described. Total wall blood flow was determined in sequential segments of small intestine from 5 to 6-month-old male, anesthetized Fischer 344 rats either 75-80 min before or after feeding, using radioactive microspheres. Oxygen saturation in submucosal arterioles and venules (50-60 micron diam) was determined throughout the intestine, using a microspectrophotometric technique. Venous O2 saturations showed considerable heterogeneity in all regions, and ranged from 0 to 77%. Arterial-venous O2 content differences (CaO2-CvO2) did not change along the fasted rat intestine, and averaged 8.2 ml O2/100 ml blood. However, CaO2-CvO2 followed a small proximal to distal gradient (proximal greater than distal) in the fed rats. Larger proximal to distal gradients (proximal greater than distal) occurred in both blood flow and O2 consumption in both groups. Feeding did not change intestinal average CaO2-CvO2. However, feeding induced a 53% increase in average O2 consumption, with the greatest increase (130%) occurring in the middle third of the intestine. Feeding induced a 42% increase in average blood flow, with the greatest increase (70%) occurring in the distal third of the intestine. The increased O2 used by the fed intestine was primarily provided by the increased blood flow. The O2 consumption gradient is assumed to reflect differences in mucosal mass along the intestine and/or differences in metabolic activity. 相似文献