全文获取类型
收费全文 | 200900篇 |
免费 | 52072篇 |
国内免费 | 5029篇 |
专业分类
耳鼻咽喉 | 3338篇 |
儿科学 | 5734篇 |
妇产科学 | 2155篇 |
基础医学 | 33602篇 |
口腔科学 | 7545篇 |
临床医学 | 25196篇 |
内科学 | 42202篇 |
皮肤病学 | 10298篇 |
神经病学 | 20486篇 |
特种医学 | 8667篇 |
外国民族医学 | 21篇 |
外科学 | 28382篇 |
综合类 | 12306篇 |
现状与发展 | 30篇 |
一般理论 | 45篇 |
预防医学 | 11944篇 |
眼科学 | 4849篇 |
药学 | 18458篇 |
66篇 | |
中国医学 | 5339篇 |
肿瘤学 | 17338篇 |
出版年
2024年 | 169篇 |
2023年 | 1129篇 |
2022年 | 3063篇 |
2021年 | 6497篇 |
2020年 | 8073篇 |
2019年 | 13606篇 |
2018年 | 13535篇 |
2017年 | 14265篇 |
2016年 | 15459篇 |
2015年 | 17224篇 |
2014年 | 18430篇 |
2013年 | 19257篇 |
2012年 | 15304篇 |
2011年 | 15171篇 |
2010年 | 15517篇 |
2009年 | 11138篇 |
2008年 | 10118篇 |
2007年 | 8477篇 |
2006年 | 7853篇 |
2005年 | 6861篇 |
2004年 | 5620篇 |
2003年 | 5340篇 |
2002年 | 4708篇 |
2001年 | 3948篇 |
2000年 | 3452篇 |
1999年 | 2499篇 |
1998年 | 1217篇 |
1997年 | 992篇 |
1996年 | 864篇 |
1995年 | 757篇 |
1994年 | 704篇 |
1993年 | 511篇 |
1992年 | 797篇 |
1991年 | 761篇 |
1990年 | 648篇 |
1989年 | 583篇 |
1988年 | 486篇 |
1987年 | 523篇 |
1986年 | 376篇 |
1985年 | 320篇 |
1984年 | 211篇 |
1983年 | 184篇 |
1982年 | 118篇 |
1981年 | 106篇 |
1980年 | 82篇 |
1979年 | 119篇 |
1978年 | 111篇 |
1975年 | 68篇 |
1974年 | 76篇 |
1973年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
991.
Effat L Kuzmin A Kasem N Meguid NA Kotb S Eisensmith RC Temtamy SA Rushdi S Woo S el-Awady M 《European journal of human genetics : EJHG》1999,7(2):259-262
A high degree of molecular heterogeneneity at the phenylalanine hydroxylase (PAH) locus was established by examining RFLP haplotypes and PAH mutations in the families of 13 Egyptians with phenylketenouria (PKU). Thirteen different haplotypes were unequivocally determined in these kindreds. Haplotypes 1.8, 3.9, 4.3, 7.8, 22.11, 27.6, and 52.8 were found segregating with normal chromosomes, whilst haplotypes 1.8, 5.9, 23.8, 32.8, the newly assigned 73.9, and two as yet incomplete but novel haplotypes were found segregating with the mutant chromosomes. There was no particular preference for a single haplotype among normal or mutant chromosomes. Nine different mutations were also identified among the 26 alleles. IVS 10nt11g (8/26), IVS 2nt5g-c (4/26), R261Q (3/26), R176X (2/26), Y206D (2/26), S231P (2/26), Y198fs [593-614del22bp]; (2/26), G46fs [136/137delG]; (1/26), and E178G (1/26). Six of these mutations (IVS 2nt5g-c, R176X, Y198fs, R261Q, S231P, and IVS 10nt11g) are common to other Mediterranean populations. Two mutations not previously reported in the Mediterranean basin were also observed (Y206D and G46fs). These intriguing preliminary findings confirm IVS 10nt11g as a major mutation among Mediterranean mutations and demonstrate the need for a more comprehensive study of Arab populations to confirm the uniqueness of the two novel mutations to the Egyptian population. 相似文献
992.
Yves de Roten Mlanie Fischer Martin Drapeau Vronique Beretta Ueli Kramer Nathalie Favre Jean‐Nicolas Despland 《Clinical psychology & psychotherapy》2004,11(5):324-331
Early therapeutic alliance is usually measured by the rating of a single session (between the third and the fifth sessions). However, there is a strong argument in favor of viewing early alliance as a developing process. This study examined the relationship between patient's rating of the helping alliance (HAq) at each session and therapy outcome. This comparison was repeated using patterns of alliance over the course of treatment. Patterns of therapeutic alliance development were detected by clustering ratings of a sample of N = 70 outpatients across four sessions of very brief psychotherapeutic intervention. Cluster analysis revealed two main patterns (shapes) of alliance development: (i) stable alliance, and (ii) linear growth pattern. These patterns are more predictive of symptom improvement and social adjustment than single ratings, whereas single ratings measuring the strength of alliance are more correlated with patient's satisfaction. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
993.
Combined effects of inhaled nitric oxide and a recruitment maneuver in patients with acute respiratory distress syndrome 总被引:1,自引:0,他引:1
Nitric oxide (NO) inhalation therapy has been employed in the management of acute respiratory distress syndrome (ARDS), in order to improve oxygenation. Several factors have been implicated as being responsible for the action of inhaled NO. Alveolar recruitment methods, such as prone positioning and a sufficient positive end expiratory pressure (PEEP), have been identified as having a positive impact on the NO response. A Recruitment maneuver (RM) was introduced for the treatment of ARDS, along with a lung protective strategy. Here, we hypothesized that a RM may further augment the oxygenation of patients treated with NO inhalation. Therefore, the effects of the inhalation of NO, either in combination with a RM, or separately, were evaluated on patients with ARDS for their enhancing action. 23 patients with ARDS were enrolled, and divided into three groups. The patients in group 1 (n=11) were treated with 5 ppm NO via inhalation, followed by a RM, applying a sustained inflation pressure of 30 - 35 cmH2O for 30 seconds. Group 2 (n=6) received a RM alone, while group 3 (n=3) was treated with NO inhalation alone. The oxygenation and hemodynamic parameters were obtained prior to, and 2, 12, and 24 h after, the respective treatment procedures. For group 1, the PaO2/FiO2 increased from its initial value of 171.8 +/- 67.8 to 203.2 +/- 90.0 2 h after NO inhalation. Further improvement was noted with the continual application of the RM reaching, 215.5 +/- 74.6 (p=0.05) and 254.2 +/- 109.5 (p < 0.05), after 12 and 24 h, respectively. Initially 7 of the subjects did not respond to NO inhalation, but 3 of these non-responders changed into responders 12 h after the RM. The changes in the PaO2/FiO2 from baseline at each time period were greater in group 1 than in the other groups, but with no statistical significance. The hemodynamics of the patients was not significantly altered during the entire study period. We conclude that the combined application of NO inhalation and a RM could be beneficial and safe for patients with ARDS, showing an enhancing effect in improvement of oxygenation. 相似文献
994.
Oh SH Kim JK Song KS Noh SM Ghil SH Yuk SH Lee JH 《Journal of biomedical materials research. Part A》2005,72(3):306-316
Sol-gel transition temperature-controllable Pluronic F127/F68 mixtures including mildly crosslinked alginate and nonsteroidal anti-inflammatory drug (ibuprofen) were prepared to evaluate their potential as tissue adhesion barrier gels. The sol-gel transition temperatures of the Pluronic mixtures could be controlled by adjusting F127/F68 ratio and polymer concentration. The mildly crosslinked alginate with still flow property provided the residence stability of Pluronic mixture gels in the body. Ibuprofen was loaded in Pluronic mixtures to reduce inflammatory response in the body and, thus, to prevent tissue adhesion. The gelation temperatures of the Pluronic mixtures were not affected by the alginate but lowered by the addition of ibuprofen. The in vitro drug release behavior and in vivo peritoneal tissue adhesion of the Pluronic mixtures with the sol-gel transition just below body temperatures were investigated. The drug release behavior from the ibuprofen (1 wt%)-loaded Pluronic mixture gels at 37 degrees C was examined using a membrane-less dissolution model. The drug in the mixture gels was released continuously up to about 45-65% of the total loading amount during the first 7 days. For in vivo evaluation of tissue anti-adhesion potential, the Pluronic mixtures with/without drug were coated on the peritoneal wall defects of rats and their tissue adhesion extents and tissue reactions (inflammatory response, granulation tissue formation, and toxicity in organs) were compared. It was observed that ibuprofen has a positive effect for the peritoneal tissue anti-adhesion. The Pluronic F127/F68/alginate/ibuprofen mixture gel (25 wt% of F127/F68 [7/3], 1 wt% ibuprofen) was highly effective for the prevention of peritoneal tissue adhesion and showed a relatively low inflammatory response and non-toxicity, and thus can be a good candidate material as a coatable or injectable tissue adhesion barrier gel. 相似文献
995.
996.
Pregnant Sprague--Dawley rats were treated once daily with 40-mg/kg cocaine or saline from gestation days (GD) 12 to 21. A third group of pregnant dams was used as a pairfed control. Male and female offspring were examined for stress endurance response as determined by the cold-water swim test on postnatal days (PND) 21, 30, 40, and 60. Male and female offspring exposed to cocaine in utero were found to have diminished tolerance and altered hormonal response to stress. Moreover, prenatal cocaine exposure has been associated with significant increases in severity of N-methyl-D-aspartate (NMDA; 35 mg/kg) behavioral responses (tail twitches, wetdog shaking, and convulsion) as compared to control. Examining the experimental groups for pain sensitivity using the tail-flick and the hot-plate methods indicated that prenatal cocaine exposure altered pain sensitivity. NMDA receptor binding studies showed an increase in receptor density in the hippocampus and hypothalamus of the cocaine-treated group. These results indicate that gestational cocaine exposure is associated with long-term alterations in response to stress, NMDA receptor, and pain sensitivity in the rat offspring. 相似文献
997.
Summary. Nested polymerase chain reaction (PCR) amplifying the morphological transforming region II (mtrII) of cytomegalovirus (CMV)
has been shown to be useful in the detection of CMV DNA in bone marrow transplant (BMT) recipients. However, there has never
been any report on mutation hot spots and subtypes of this open reading frame. Using primers derived from sequences upstream
and downstream of mtrII (ORF 79), CMV DNA from peripheral blood leukocytes (PBL) and conventional CMV culture of 16 BMT recipients
were amplified by PCR, cloned into pUC118, and sequenced. The amino acid sequences were predicted using the standard triplet
code. The DNA sequences obtained from direct amplification of CMV in PBL obtained from the 16 patients were 100% identical
to the corresponding ones obtained by amplification of CMV DNA extracted from conventional CMV culture. Within mtrII (ORF
79), hot spot single base mutations were observed at positions +40 (G→A), +123 (A→G), +213 (T→C), and +219 (T→C). However,
because of third base degeneracy, only amino acid 14 was changed from valine to isoleucine in the predicted protein of 13
patients. This corresponded to the hot spot mutation at position +40 (GTC→ATC), while the rest were silent mutations. An insertion
of 3 bases (ACG) was observed in the CMV DNA of 10 patients at positions +91 to +93, leading to a threonine insertion at amino
acid 31 in these patients. For patient no. 147 there was a 65 bp deletion in the CMV DNA amplified later in the course of
BMT as compared with that early in the course. This gave rise to a frame shift mutation and a change of more than 70% in the
predicted amino acid sequence of the protein.
Accepted October 14, 1998 Received May 20, 1998 相似文献
998.
G. C. Park O. Z. Roy A. Warrick C. Côté 《Medical & biological engineering & computing》1979,17(2):246-248
For the nonverbal cerebral palsy child, communication with the outside world is a major problem. With those c.p. children
who do not suffer complete limb paralysis, limb movement is at least very spastic and prevents them from using normal keyboard
writing devices or instruments. During recent years a number of special communication devices have been developed for the
use of such children and these range from simple mechanical systems to sophisticated, but costly, electronic systems. The
paper describes a simple, inexpensive, yet useful, mechanicalpointer system for such handicapped children, which can be used
for a multiaddress communications system as well as a drawing or art instrument for severely involved children. 相似文献
999.
1000.
M. El‐Batawy A. S. Zahran S. A. Madkor C. J. Smith 《Food and Agricultural Immunology》1993,5(1):57-60
An enzyme‐linked immunosorbent assay (ELISA) for the detection of porcine pepsin in milk‐clotting enzyme preparations has been developed. The assay is capable of detecting porcine pepsin in the range 1 μgto 1 mg ml‐1 without enhancement or modification. The specificity of the technique was studied by inhibition assay. Slight cross‐reactions with bovine rennet and Mucor miehei rennet occurred at high concentrations (1.0 mg ml‐1). The ELISA used in this investigation appears to provide a quick, sensitive and specific method for the detection of porcine pepsin and has potential applications in the dairy industry. 相似文献