全文获取类型
收费全文 | 8186篇 |
免费 | 341篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 75篇 |
儿科学 | 150篇 |
妇产科学 | 150篇 |
基础医学 | 1218篇 |
口腔科学 | 165篇 |
临床医学 | 725篇 |
内科学 | 1836篇 |
皮肤病学 | 204篇 |
神经病学 | 487篇 |
特种医学 | 680篇 |
外科学 | 1008篇 |
综合类 | 66篇 |
预防医学 | 245篇 |
眼科学 | 87篇 |
药学 | 790篇 |
中国医学 | 93篇 |
肿瘤学 | 659篇 |
出版年
2023年 | 45篇 |
2022年 | 140篇 |
2021年 | 221篇 |
2020年 | 103篇 |
2019年 | 150篇 |
2018年 | 170篇 |
2017年 | 150篇 |
2016年 | 208篇 |
2015年 | 273篇 |
2014年 | 302篇 |
2013年 | 409篇 |
2012年 | 541篇 |
2011年 | 521篇 |
2010年 | 388篇 |
2009年 | 256篇 |
2008年 | 411篇 |
2007年 | 399篇 |
2006年 | 347篇 |
2005年 | 309篇 |
2004年 | 263篇 |
2003年 | 225篇 |
2002年 | 170篇 |
2001年 | 166篇 |
2000年 | 163篇 |
1999年 | 137篇 |
1998年 | 131篇 |
1997年 | 130篇 |
1996年 | 134篇 |
1995年 | 95篇 |
1994年 | 87篇 |
1993年 | 87篇 |
1992年 | 67篇 |
1991年 | 69篇 |
1990年 | 69篇 |
1989年 | 93篇 |
1988年 | 79篇 |
1987年 | 72篇 |
1986年 | 66篇 |
1985年 | 58篇 |
1984年 | 67篇 |
1981年 | 43篇 |
1980年 | 55篇 |
1976年 | 42篇 |
1975年 | 38篇 |
1965年 | 50篇 |
1964年 | 50篇 |
1963年 | 47篇 |
1962年 | 41篇 |
1961年 | 40篇 |
1960年 | 65篇 |
排序方式: 共有8638条查询结果,搜索用时 15 毫秒
991.
Hirotoshi IMAMURA Shoichi TANI Hidemitsu ADACHI Ryu FUKUMITSU Tadashi SUNOHARA Nobuyuki FUKUI Yoshihiro OMURA Natsuhi SASAKI Tomoaki AKIYAMA Tatsumaru FUKUDA Shinji KAJIURA Masashi SHIGEYASU Kento ASAKURA Ryo HORII Nobuyuki SAKAI 《Neurologia medico-chirurgica》2022,62(5):223
Vasospasm, initial neurological damage, rebleeding, and periprocedural complications are associated prognostic factors for clinical outcomes after aneurysmal subarachnoid hemorrhage (SAH). In this study, factors related to delayed ischemic neurological deficit (DIND) are evaluated using data from our institute for the last 18 years. Data from 2001 to 2018 of patients with aneurysmal SAH who underwent surgical clipping (SC) or endovascular coiling (EC) within 7 days of onset were retrospectively analyzed. Cases of mortality within 5 days after treatment were excluded. Multivariate analysis was used to identify the risk factors for DIND. In total, 840 cases of SAH were assessed; among these cases, 384 (45.7%) and 456 (54.3%) were treated with SC and EC, respectively. The frequency of DIND in the EC group was significantly less than that in the SC group (11.8% vs. 17.7%; p = 0.016). In the results of multivariate analysis, internal carotid artery (ICA) aneurysm and hemorrhagic complications were the risk factors for DIND. Cilostazol administration and EC were significant factors for vasospasm prevention after aneurysmal SAH (odds ratio of ICA aneurysm: 1.59, hemorrhagic complications: 1.76, SC: 1.51, and cilostazol administration: 0.51, respectively). Cilostazol administration was also a significant factor in patients who were treated with EC. ICA aneurysm, treatment strategy, hemorrhagic complications, and cilostazol administration were associated with DIND. Oral administration of cilostazol and avoiding hemorrhagic complications were effective in DIND prevention. If both treatments are available for ruptured aneurysms, clinicians should choose EC on the basis of its ability to prevent DIND. 相似文献
992.
Purpose
Breast cancer displays varying molecular and clinical features. The ability to form breast tumors has been shown by several studies with aldehyde dehydrogenase 1 (ALDH1) positive cells. The aim of this study is to investigate the association between ALDH1 expression and clinicopathologic characteristics of invasive ductal carcinoma.Methods
We investigated breast cancer tissues for the prevalence of ALDH1+ tumor cells and their prognostic value. The present study included paraffin-embedded tissues of 70 patients with or without recurrences. We applied immunohistochemical staining for the detection of ALDH1+ cells. Analysis of the association of clinical outcomes and molecular subtype with marker status was conducted.Results
ALDH1+ and ALDH1- tumors were more frequent in triple-negative breast cancers and in luminal A breast cancers, respectively (p<0.01). ALDH1 expression was found to exert significant impact on disease free survival (DFS) (ALDH1+ vs. ALDH1-, 53.1±6.7 months vs. 79.2±4.7 months; p=0.03) and overall survival (OS) (ALDH1+ vs. ALDH1-, 68.5±4.7 months vs. 95.3±1.1 months; p<0.01). In triple-negative breast cancer (TNBC) patients, DFS and OS showed no statistical differences according to ALDH1 expression (ALDH1+ vs. ALDH1-, 45.3±9.4 months vs. 81.3±7.4 months, p=0.52; 69.0±7.5 months vs. 91.3±6.3 months, p=0.67). However, non-TNBC patients showed significant OS difference between ALDH1+ and ALDH1- tumors (ALDH1+ vs. ALDH1-, 77.6±3.6 months vs. 98.0±1.0 months; p=0.04) with no statistical difference of DFS (ALDH1+ vs. ALDH1-, 60.5±8.0 months vs. 81.8±4.6 months; p=0.27).Conclusion
Our findings suggest that the expression of ALDH1 in breast cancer may be associated with TNBC and poor clinical outcomes. On the basis of our findings, we propose that ALDH1 expression in breast cancer could be correlated with poor prognosis, and may contribute to a more aggressive cancer phenotype. 相似文献993.
BACKGROUND: The carina level has been shown to be near the pericardial reflectionand can easily be identified as a landmark on a routine chestradiography. The purpose of this study was to reveal a simplemethod to predict the adequate central venous catheter (CVC)depth, hereby facilitating safe positioning of the CVC tip. METHODS: Central venous catheterization was performed via the right internaljugular vein (IJV) or the right subclavian vein (SCV). The CVCwas placed at a depth derived by adding the length between theneedle insertion point and the clavicular notch and the verticallength between the clavicular notch and the carina on the chestradiograph. The distance between the CVC tip and the carinawas measured on the postoperative chest radiograph. RESULTS: The tip position of 100 CVCs placed via the right IJV was 0.1(1.1) cm [mean (SD)] below the carina (95% CI: 0.3 cm belowcarina0.2 cm above carina) and the tip positionof 153 CVCs placed via the right SCV was 0.0 (1.2) cm [mean(SD)] below the carina (95% CI: 0.2 cm below carina0.2 cmabove carina). There were nine outliers (two in IJV group andseven in SCV group). CONCLUSIONS: When CVCs are inserted to a depth derived by adding the lengthbetween the needle insertion point and the clavicular notchand the vertical length between the clavicular notch and thecarina, the CVC tip can be reliably placed near the carina level. 相似文献
994.
Rat spinal dorsal horn neurons in slice preparations perfused with Ringer solution containing 0.5-1 microM TTX and/or 10-20 mM tetraethylammonium at 29 degrees C, were studied by using a single microelectrode voltage-clamp technique. Slow persistent inward currents were recorded during depolarizing voltage commands to membrane potentials positive to about -40 mV. The inward current was depressed by removing external Ca, or by adding 0.1-0.2 mM Cd, 5 mM Co or 0.1 mM verapamil, and was increased by adding Ba or Bay-K 8644. Substance P (SP) augmented a persistent slow inward Ca-sensitive current in a dose-dependent manner. It is suggested that this effect may be instrumental in generating the SP-evoked slow depolarization, increase in membrane excitability, and the 'bursting' behavior in the immature rat dorsal horn neurons. In addition, in some neurons SP reduced the M-like current, which effect may contribute to, but not explain, generation of the SP-induced slow depolarization. 相似文献
995.
996.
997.
A Dose-Response Analysis of Methoxychlor-Induced Alterations of Reproductive Development and Function in the Rat 总被引:6,自引:8,他引:6
GRAY L. EARL JR; OSTBY JOSEPH; FERRELL JANET; REHNBERG GEORGIA; LINDER RALPH; COOPER RALPH; GOLDMAN JEROME; SLOTT VALERIE; LASKEY JOHN 《Toxicological sciences》1989,12(1):92-108
A Dose-Response Analysis of Methoxychlor-Induced Alterationsof Reproductive Development and Function in the Rat. GRAY, L.E., JR., OSTBY, J., FERRELL, J., REHNBERG, G., LINDER, R., COOPER,R., GOLDMAN, J., SLOTT, V., AND LASKEY, J. (1989). Fundam. Appl.Toxicol12, 92108. In the present study rats were dosed fromweaning, through puberty and gestation, to Day 15 of lactationwith methoxychlor at 25, 50, 100, or 200 mg/kg/day. Morphologicallandmarks of puberty were measured, including the ages at vaginalopening, first estrus, and first estrous cycle in females andat preputial separation in males. In the female, estrous cyclicity,fertility, litter size, number of implantation sites, organweights, and ovarian and uterine histology were also measured.The viability of the offspring (F1) and their fertility wereevaluated using a continuous breeding protocol. Males were necropsiedafter breeding, the reproductive organs were weighed, and thecauda epididymal sperm counts were determined. One testis wasused for histopathology, while the other was used to quantifyinterstitial fluid (IF) content, IF testosterone concentration,and testicular sperm production. Testosterone and an drogen-bindingprotein were measured in the caput epididymis, and sperm motilityand morphology were evaluated from a caudal sample. The serumand pituitary were saved for hormonal determinations. Methoxychloraccelerated the age at vaginal opening and first estrus, andthe vaginal smears were cornified. Growth was retarded at 100and 200 mg/kg/day and fertility was reduced when the femaleswere bred with untreated or similarly treated males. In thehighest- dose group, the mated females went from constant estrusinto pseudopregnancy following mating, but they had no implants.In males, methoxychlor treatment markedly reduced growth, seminalvesicle weight, cauda epididymal weight, caudal sperm content,and pituitary weight. Puberty was delayed in the two highest-dosagegroups. Testicular sperm measures were much less affected thancaudal measures. Testis weight and histology were slightly affected,and testicular sperm production, sperm morphology, and motilitywere unaffected. Endocrine function of the testes and pituitarywas altered by methoxychlor administration. Leydig cell testosteroneproduction, in response to human chorionic gonadotropin challenge,was reduced and pituitary levels of prolactin, thyroid-stimulatinghormone (TSH), and follicle-stimulating hormone (FSH) were altered.In contrast, serum levels of prolactin, FSH, and luteinizinghormone were unaffected. Serum TSH was reduced by 50% of controlat 100 and 200 mg/kg/day, while pituitary levels were increased.Gonadotropin-releasing hormone concentration in the mediobasalhypothalamus was also elevated. In spite of the many reproductivealterations, the fertility of treated males was not reducedwhen they were mated with untreated females. Growth and viabilityof the offspring (F1) from the 50 mg/kg/day treatment groupwere normal, but in the females, vaginal opening was accelerated,estrous cyclicity was abnormal in the rats during middle age,and fecundity was reduced. 相似文献
998.
A male infant is described in whom congenital anomalies were recognized prenatally by ultrasound examination. The infant was delivered following spontaneous labor and died approximately 15 min after birth. An autopsy revealed major anomalies in the central nervous system (holoprosencephaly with premaxillary agenesis), the gastrointestinal system (esophageal atresia) and the heart (tetralogy of Fallot). Chromosomal studies revealed recombinant chromosome 5 [46,XY, rec(5), dup q, inv(5)(p15q32)], resulting in partial trisomy 5q and partial monosomy 5p. Cytogenetic investigation of the family revealed a pericentric inversion of chromosome 5 in the father and paternal grandmother, 46,XY (and XX, respectively,) inv(5)(p15q32). The congenital anomalies in this infant are more extensive and severe than previously reported in cases of recombination aneusomy involving chromosome 5. 相似文献
999.
Kim YH; de Kretser DM; Temple-Smith PD; Hearn MT; McFarlane JR 《Molecular human reproduction》1997,3(4):307-313
Using mechanical and chemical dissection methods, fibrous sheath was
isolated both from normal ejaculated human spermatozoa and from rabbit
cauda epididymal spermatozoa. The same techniques did not produce a pure
preparation of fibrous sheath from ejaculated rabbit spermatozoa,
suggesting that further cross-linking and stabilization of sperm structures
occurs in response to components of the seminal plasma. The isolation
procedures were monitored by phase contrast microscopy and the purity of
the fibrous sheath was verified by electron microscopy. Sodium dodecyl
sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of isolated human
fibrous sheath revealed at least 14 protein bands of which the most
intensely stained were of molecular weight 84, 72, 66.2, 57, 32 and 28.5
kDa. The rabbit fibrous sheath revealed at least 10 protein bands, of which
the most intensely stained were 35.2, 32.7 and 28.5 kDa. The amino acid
composition of the purified fibrous sheath from human and rabbit
spermatozoa was similar, being high in aspartic acid and/or asparagine and
glutamic acid and/or glutamine, serine, alanine, leucine, lysine and
glycine, but low in histidine, tyrosine and isoleucine. This composition is
similar to that reported for the rat and suggests that mammalian sperm tail
fibrous sheaths are composed of similar types of proteins, although there
are apparent differences in protein components between species.
相似文献
1000.
DS Keller RN Tahilramani JR Flores-Gonzalez S. Ibarra EM Haas 《Surgical endoscopy》2016,30(6):2192-2198