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Actin cytoskeleton is crucial to support spermatogenesis in the mammalian testis. However, the molecular mechanism(s) underlying changes of actin cytoskeletal organization in response to cellular events that take place across the seminiferous epithelium (e.g., self-renewal of spermatogonial stem cells, germ cell differentiation, meosis, spermiogenesis, spermiation) at specific stages of the epithelial cycle of spermatogenesis remain largely unexplored. This, at least in part, is due to the lack of suitable study models to identify the crucial regulatory proteins and to investigate how these proteins work in concert to support actin dynamics. Much of the information on the role of actin binding proteins in the literature, namely the actin bundling proteins, actin nucleation proteins and motor proteins, are either findings based on genetic models or morphological analyses. While this information is helpful to delineate the function of these proteins to support spermatogenesis, they are not helpful to identify the regulatory signaling proteins, the signaling pathways and the cascade of events to modulate actin cytoskeleton dynamics. Recent studies based on the use of toxicant models, both in vitro and in vivo, however, have bridged this gap by identifying putative regulatory and signaling proteins of actin cytoskeleton. Herein, we summarize and critically evaluate these findings. We also provide a hypothetical model by which actin cytoskeletal dynamics in Sertoli cells are regulated, which in turn supports spermatid transport across the seminiferous epithelium, and at the blood-testis barrier (BTB) during the epithelial cycle of spermatogenesis. 相似文献
3.
《The surgeon》2022,20(4):e100-e104
IntroductionUndescended testis (UDT) is a clinical diagnosis and a common reason for referral to paediatric urology outpatients. Our aim was to assess current referral patterns at our unit and to identify predictive factors that may better aid primary care physicians (PCP) in diagnosing UDT based on history and physical exam.MethodsA retrospective analysis of referrals to outpatients from 2014 to 2016 was performed to assess current referral patterns including referral source, age, reason for referral and outcome following assessment by a single consultant paediatric urologist.A prospective analysis of new referrals was performed to identify predictive factors which may aid in the diagnosis of UDT including gestational age, presence of scrotal asymmetry and previously obtained imaging.ResultsFrom 2014 to 2016, 259 boys were referred with suspected UDT. The majority of referrals were received from PCPs (62%) followed by Neonatology (29%), Paediatrics (8%) and general surgery (1%). Median age at time of assessment was 29 (5–180) months. One hundred and eight (41.7%) boys were diagnosed with UDT.There were 74 boys assessed prospectively. Median age at assessment was 24.5 (6–171) months. We identified 3 predictors of a diagnosis of UDT; history of prematurity (p = 0.001), UDT mentioned to the parents at birth (p = 0.027) and scrotal asymmetry on examination (p < 0.001). Greatest diagnostic inaccuracy was found in boys referred beyond one year of age (27.7%). In this cohort, the absence of all three risk factors was associated with a negative predictive value of 94.1%.ConclusionThe majority of boys with suspected UDT are referred beyond the age recommended for orchidopexy (6–12 months). The majority of boys referred for assessment did not have UDT. We have identified three predictive factors that may aid referring physicians when assessing boys, particularly those older than 1 year. 相似文献
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Homologous testis transplantation in dogs 总被引:4,自引:0,他引:4
Evert J. Barten Hayrabet Garybian Pieter J. Klopper Donald W. W. Newling 《Transplant international》1997,10(5):362-368
There is growing interest in the possible use of homologous testis transplantation for the treatment of anorchia and male
infertility. In order to test the surgical and immunological feasibility of this therapy, three series of experimental studies
of homologous testis transplantation were carried out in dogs. In the first pilot study, four beagles from the same litter
were transplanted using microsurgical techniques for end-to-end anastomosis of the testicular vessels and the vas deferens.
These dogs received cyclosporin A (CyA) for 3 months after transplantation. The longest functional graft survival in this
series was 163 days, strongly suggesting that long-term survival of a homologously transplanted testis graft is possible.
A second series of operations was performed on ten mongrel dogs. The same surgical technique was employed and the series was
divided into three groups.
Group 1 received CyA monotherapy, group 2 a combination of CyA and prednisolone, and group 3 received no immunosuppression.
The average graft survival time in this series was 18 days, significantly less than the 71 days in the first series. The dogs
in group 2, however, had graft survival times that were three times longer than those in the other two groups, suggesting
that CyA in combination with prednisolone yields the best graft survival. In the third series, five littermates received a
testis graft after castration. Immunosuppression was achieved by administration of CyA and prednisolone for 3 months. In three
out of five animals, the graft survived until the immunosuppressive therapy was suspended. Histological biopsies of the graft
3 months after transplantation showed the same maturation of sperm cells as in the control testis of the same dog. The results
of the last series suggest that long-term survival of homologously transplanted testis grafts in dogs is, indeed, possible
with the aid of CyA and prednisolone.
Received: 14 August 1996 Received after revision: 21 March 1997 Accepted: 24 April 1997 相似文献
6.
Summary Postnatal formation of the Blood-Testis Barrier (BTB) in the rat was studied by either fixation in hypertonic fixative or employing lanthanum tracer. After 15 days of age, meiosis has reached different stages of spermatogenesis in differnt zones of the seminiferous cords. Only in those parts where germ cells are in the pachytene stage of meiosis do Sertoli cells form an effective barrier or tight compartment. Between 16 and 19 days of age, final formation of the BTB, which is to be found in the adult rat testis, occurs by zygotene and then leptotene stages successively entering the tight compartment. Thus, formation of a BTB by Sertoli cells does not occur synchronously along the length of the seminiferous cord but in accordance with the stage of meiosis of the associated germ cells. 相似文献
7.
Summary: For the quantitative determination of the testicular size or volume, two groups of apparatus are available: on the one hand, model testes, which are extremely valuable in longitudinal and cross-sectional studies during the period of pubescence, and on the other hand, measuring devices, with which the testicular dimensions can be specified. The latter instruments are helpful chiefly during the adolescent years and the diagnosis of problems surrounding fertility. The testicular volume can be calculated subsequently from the specific testicular measurements. The formula, for computing the volume of an ellipsoid, seems to be the most suitable for this purpose. Appliances also have been developed, which allow the largest (longitudinal) dimension (in mm) and the testicular volume (in cm3) to be read off simultaneously. A tonometer can be useful to quantitatively estimate the testicular consistency, which is a parameter of the testicular integrity at the level of tubular function (spermatozoa production). 相似文献
8.
2-乙氧基乙醇急性染毒大鼠血清和睾丸某些抗氧化指标的变化 总被引:1,自引:0,他引:1
目的 观察2-乙氧基乙醇(2-Ethoxythanol,EE)急性染毒对SD大鼠血清和睾丸某些抗氧化指标的变化,探讨EE致睾丸损伤的可能机制。方法 选择健康雄性SD大鼠,体重180-220g。随机分为对照组、EE800、1600和3200mg/kg组4组,每组24只。采取一次性灌胃染毒。于灌胃后12、24、48和72h,将各组动物随机处死6只,留取动物血液、睾丸,制备血清和睾丸匀浆,测定血清和睾丸匀浆脂质过氧化物(LPO)水平、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性,以及血清铜蓝蛋白(CP)活性。结果 与对照组比较,各染毒组睾/体比明显下降(P<0.05),睾丸匀浆LPO水平和血清CP活性增高。染毒12、24h,血清CAT、睾丸匀浆CAT和SOD活性增高,而染毒48、72h后,血清CAT、睾丸匀浆CAT和SOD活性显著降低(P<0.05)。EE各染毒组血清LPO水平和SOD活性变化不明显。结论 推测EE毒作用的靶器官可能是睾丸,睾丸抗氧化功能的改变是EE致睾丸毒性的可能机制。 相似文献
9.
男科学组织工程研究前景 总被引:4,自引:3,他引:1
利用组织工程技术进行细胞移植的设想 ,已经为男科领域的组织再建工作提供了许多可能。为改善、修复或替代现有组织的功能 ,组织工程的应用研究 ,已经在睾丸间质细胞、睾丸假体、阴茎海绵体、阴茎假体等方面开展。虽然大多数再建工作仍然停留在实验阶段 ,但是有些技术也被用于临床 ,并取得满意的结果。本文简要地综述了组织工程在男科学的应用 相似文献
10.
W N Kühn-Velten 《Andrologia》1992,24(2):109-111
In addition to the well-known control circuits involved in the regulation and adaptation of testicular androgen biosynthesis, it is proposed that two new control strategies are involved in the maintenance of steady-state testosterone secretion rates by testicular Leydig cells. Cytochrome P450XVII (steroid-17 alpha-monooxygenase/steroid-17,20-lyase), one key enzyme in steroid hormone biosynthesis, responds to external human choriogonadotropin stimulation with an oxygen-dependent and substrate flux-dependent inactivation and decomposition, and increased substrate availability decreases the efficiency of androgen formation in favour of abortive intermediate leakage. These results are discussed as a paradigm of substrate-dependent modulation of cytochrome P450 activities. 相似文献